Desktop. Fix input methods on JBR, disable input methods when we lose focus (#881)

### Rerequest focus on main component when we need to type using input
methods
Fixes JetBrains/compose-multiplatform#2628

The issue was because of 2 things:
- we used a hack to force a focused event
(`component.inputContext.dispatchEvent(focusGainedEvent)`
- JBR added optimization to ignore focus on the same element (thanks
@AiHMin for investigation
[here](JetBrains/compose-multiplatform#2628 (comment))).
In Compose we have only one element.
Because optimization is correct, and the hack depends on the internals,
it isn't right to fix it in JBR, we should fix it in Compose.
Furthermore, even without JBR changes, this hack didn't complete work -
we can't for example use it for disabling input methods (see the next
point).

In this PR we also use a hack unfortenutely - we refocus the root
component, focusing on invisible component first. That leads to another
issue with acccessibility, but we fix it
[here](#885)).

A proper fix should be switching to native code, or making an API in JBR
(but other vendors still be unsupported).

### Don't show input methods popup if there is no focused TextField 

Previously we showed a popup, even if there are no focused textfield:

![image](https://github.com/JetBrains/compose-multiplatform-core/assets/5963351/82e3543f-11f4-4013-8da5-d782b824ed2c)
Now we don't show it if we isn't in a textfield.
P.S. only on Windows/Linux for now, on macOs Swing seems has [a
bug](JetBrains/compose-multiplatform#3839)

## Testing
Tested manually on:
1. Windows, Chinese/Korean/Japanese, OpenJDK/JBR 17, Accessibility
enabled/disabled, ComposeWindow/ComposePanel
2. macOs, Chinese, OpenJDK/JBR 17, Accessibility enabled/disabled
4. Linux, Chinese layout, OpenJDK 17

Author: igordmn

compose/ui/ui/src/desktopMain/kotlin/androidx/compose/ui/awt/ComposeBridge.desktop.kt

@@ -54,6 +54,11 @@ import org.jetbrains.skiko.*
  * Provides a base implementation for integrating a Compose scene with AWT/Swing.
  * It allows setting Compose content by [setContent], this content should be drawn on [component].
  *
+ * This bridge contain 2 components that should be added to the view hirarachy:
+ * [component] the main visible Swing component, on which Compose will be shown
+ * [invisibleComponent] service component used to bypass Swing issues:
+ * - for forcing refocus on input methods change
+ *
  * Inheritors should call [attachComposeToComponent], so events that came to [component] will be transferred to [ComposeScene]
  */
 internal abstract class ComposeBridge(
@@ -66,7 +71,10 @@ internal abstract class ComposeBridge(
         mainOwnerProvider = { scene.mainOwner }
     )
 
+    private val _invisibleComponent = InvisibleComponent()
+
     abstract val component: JComponent
+    val invisibleComponent: Component get() = _invisibleComponent
 
     abstract val renderApi: GraphicsApi
 
@@ -86,16 +94,30 @@ internal abstract class ComposeBridge(
 
     private var window: Window? = null
 
+    private fun refocus() {
+        if (component.isFocusOwner) {
+            _invisibleComponent.requestFocusTemporary()
+            component.requestFocus()
+        }
+    }
+
     private val platformComponent: PlatformComponent = object : PlatformComponent {
         override fun enableInput(inputMethodRequests: InputMethodRequests) {
             currentInputMethodRequests = inputMethodRequests
             component.enableInputMethods(true)
-            val focusGainedEvent = FocusEvent(focusComponentDelegate, FocusEvent.FOCUS_GAINED)
-            component.inputContext.dispatchEvent(focusGainedEvent)
+            // Without resetting the focus, Swing won't update the status (doesn't show/hide popup)
+            // enableInputMethods is design to used per-Swing component level at init stage,
+            // not dynamically
+            refocus()
         }
 
         override fun disableInput() {
             currentInputMethodRequests = null
+            component.enableInputMethods(false)
+            // Without resetting the focus, Swing won't update the status (doesn't show/hide popup)
+            // enableInputMethods is design to used per-Swing component level at init stage,
+            // not dynamically
+            refocus()
         }
 
         override val locationOnScreen: Point
@@ -181,6 +203,7 @@ internal abstract class ComposeBridge(
 
     @OptIn(ExperimentalComposeUiApi::class)
     protected fun attachComposeToComponent() {
+        component.enableInputMethods(false)
         component.addInputMethodListener(object : InputMethodListener {
             override fun caretPositionChanged(event: InputMethodEvent?) {
                 if (isDisposed) return
@@ -393,6 +416,12 @@ internal abstract class ComposeBridge(
             override val touchSlop: Float get() = with(platformComponent.density) { 18.dp.toPx() }
         }
     }
+
+    private class InvisibleComponent : Component() {
+        fun requestFocusTemporary(): Boolean {
+            return super.requestFocus(true)
+        }
+    }
 }
 
 private fun ComposeScene.onMouseEvent(

compose/ui/ui/src/desktopMain/kotlin/androidx/compose/ui/awt/ComposePanel.desktop.kt

@@ -119,6 +119,7 @@ class ComposePanel @ExperimentalComposeUiApi constructor(
         if (bridge != null) {
             bridge!!.dispose()
             super.remove(bridge!!.component)
+            super.remove(bridge!!.invisibleComponent)
             bridge = null
         }
     }
@@ -193,6 +194,7 @@ class ComposePanel @ExperimentalComposeUiApi constructor(
         if (bridge == null) {
             bridge = createComposeBridge()
             initContent()
+            super.add(bridge!!.invisibleComponent, Integer.valueOf(1))
             super.add(bridge!!.component, Integer.valueOf(1))
         }
     }

compose/ui/ui/src/desktopMain/kotlin/androidx/compose/ui/awt/ComposeWindowDelegate.desktop.kt

@@ -93,11 +93,13 @@ internal class ComposeWindowDelegate(
 
         init {
             layout = null
+            super.add(bridge.invisibleComponent, 1)
             super.add(bridge.component, 1)
         }
 
         fun dispose() {
             super.remove(bridge.component)
+            super.remove(bridge.invisibleComponent)
         }
     }