Bugfix: Clear focused views when FocusState becomes false

[fhasse95]

This PR fixes focus clearing for SkipUI views on Android.

Previously, .focused(...) requested focus when the bound value matched, but it did not clear the native Compose focus when the bound value changed away from the focused value. This could leave text fields focused even after setting a FocusState<Bool> binding to false.

The focus modifier now tracks whether the view is currently focused and clears the Compose focus manager when the binding no longer matches.

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