Fix InputDecorator suffixIcon color when in error and hovered (#149643)

## Description

This PRs makes the `InputDecoration.suffixIcon` color compliant with the M3 spec when in error state and hovered.

From M3 spec, the color should be `onErrorContainer`, see https://m3.material.io/components/text-fields/specs#e4964192-72ad-414f-85b4-4b4357abb83c

![image](https://github.com/flutter/flutter/assets/840911/1d8d7bb6-608f-4783-aff5-2123392c4dc1)

## Related Issue

Fixes flutter/flutter#149410.

## Tests

Updates 2 tests.

Author: bleroux

dev/tools/gen_defaults/generated/used_tokens.csv

@@ -252,6 +252,7 @@ md.comp.filled-text-field.error.focus.trailing-icon.color,
 md.comp.filled-text-field.error.hover.active-indicator.color,
 md.comp.filled-text-field.error.hover.label-text.color,
 md.comp.filled-text-field.error.hover.supporting-text.color,
+md.comp.filled-text-field.error.hover.trailing-icon.color,
 md.comp.filled-text-field.error.label-text.color,
 md.comp.filled-text-field.error.leading-icon.color,
 md.comp.filled-text-field.error.supporting-text.color,

dev/tools/gen_defaults/lib/input_decorator_template.dart

@@ -124,10 +124,10 @@ class _${blockName}DefaultsM3 extends InputDecorationTheme {
     if (states.contains(MaterialState.disabled)) {
       return ${componentColor('md.comp.filled-text-field.disabled.trailing-icon')};
     }
-    if (states.contains(MaterialState.error)) {${componentColor('md.comp.filled-text-field.error.trailing-icon') == componentColor('md.comp.filled-text-field.error.focus.trailing-icon') ? '' : '''
+    if (states.contains(MaterialState.error)) {
       if (states.contains(MaterialState.hovered)) {
         return ${componentColor('md.comp.filled-text-field.error.hover.trailing-icon')};
-      }
+      }${componentColor('md.comp.filled-text-field.error.trailing-icon') == componentColor('md.comp.filled-text-field.error.focus.trailing-icon') ? '' : '''
       if (states.contains(MaterialState.focused)) {
         return ${componentColor('md.comp.filled-text-field.error.focus.trailing-icon')};
       }'''}

packages/flutter/lib/src/material/input_decorator.dart

@@ -4748,6 +4748,9 @@ class _InputDecoratorDefaultsM3 extends InputDecorationTheme {
       return _colors.onSurface.withOpacity(0.38);
     }
     if (states.contains(MaterialState.error)) {
+      if (states.contains(MaterialState.hovered)) {
+        return _colors.onErrorContainer;
+      }
       return _colors.error;
     }
     return _colors.onSurfaceVariant;

packages/flutter/test/material/input_decorator_test.dart

@@ -5786,9 +5786,7 @@ void main() {
           );
 
           final ThemeData theme = Theme.of(tester.element(findSuffixIcon()));
-          // TODO(bleroux): based on M3 spec, it should be theme.colorScheme.onErrorContainer.
-          // See https://github.com/flutter/flutter/issues/149410.
-          final Color expectedColor = theme.colorScheme.error;
+          final Color expectedColor = theme.colorScheme.onErrorContainer;
           expect(getSuffixIconStyle(tester).color, expectedColor);
         });
       });
@@ -6262,9 +6260,7 @@ void main() {
           );
 
           final ThemeData theme = Theme.of(tester.element(findSuffixIcon()));
-          // TODO(bleroux): based on M3 spec, it should be theme.colorScheme.onErrorContainer.
-          // See https://github.com/flutter/flutter/issues/149410.
-          final Color expectedColor = theme.colorScheme.error;
+          final Color expectedColor = theme.colorScheme.onErrorContainer;
           expect(getSuffixIconStyle(tester).color, expectedColor);
         });
       });