explicitly add the aria-hidden="true" attribute

The `Hidden` component only adds the `aria-hidden` by default if the
`Focusable` feature is passed. In our case we don't want it to be
focusable so therefore we didn't pass this feature flag.

Because we didn't pass the `Focusable` feature, the `display: hidden`
was used which makes it completely unfocusable to the keyboard of the
user which is what we want.

However, the VoiceOver cursor _can_ get into those elements. Adding the
`aria-hidden` manually to these tabs solves the issue.

packages/@headlessui-react/src/components/tabs/tabs.tsx

@@ -589,7 +589,7 @@ function PanelFn<TTag extends ElementType = typeof DEFAULT_PANEL_TAG>(
   }
 
   if (!selected && (theirProps.unmount ?? true) && !(theirProps.static ?? false)) {
-    return <Hidden as="span" {...ourProps} />
+    return <Hidden as="span" aria-hidden="true" {...ourProps} />
   }
 
   return render({

packages/@headlessui-vue/src/components/tabs/tabs.ts

@@ -528,7 +528,7 @@ export let TabPanel = defineComponent({
       }
 
       if (!selected.value && props.unmount && !props.static) {
-        return h(Hidden, { as: 'span', ...ourProps })
+        return h(Hidden, { as: 'span', 'aria-hidden': true, ...ourProps })
       }
 
       return render({