Fix ClassCastException in clearFocusAndMaybeRefocus when EditText is detached

On Android <= 9 (SDK_INT <= P) in touch mode, clearFocusAndMaybeRefocus
casts rootView to ViewGroup unconditionally. getRootView() returns the
view itself when the view is detached from the window, so an IME editor
action delivered over Binder that races the removal of the EditText from
the hierarchy crashes the app with:

  java.lang.ClassCastException: com.facebook.react.views.textinput.ReactEditText
  cannot be cast to android.view.ViewGroup

Use a safe cast and fall back to a plain clearFocus(): when the view is
already detached there is no focus to move, so the descendant-focusability
workaround is not needed.

Author: shahidrogers

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactEditText.kt

@@ -380,11 +380,20 @@ public open class ReactEditText public constructor(context: Context) : AppCompat
       // Avoid refocusing to a new view on old versions of Android by default
       // by preventing `requestFocus()` on the rootView from moving focus to any child.
       // https://cs.android.com/android/_/android/platform/frameworks/base/+/bdc66cb5a0ef513f4306edf9156cc978b08e06e4
-      val rootViewGroup = rootView as ViewGroup
-      val oldDescendantFocusability = rootViewGroup.descendantFocusability
-      rootViewGroup.descendantFocusability = ViewGroup.FOCUS_BLOCK_DESCENDANTS
-      super.clearFocus()
-      rootViewGroup.descendantFocusability = oldDescendantFocusability
+      //
+      // getRootView() returns the view itself when it is detached from the window, so the root
+      // is not necessarily a ViewGroup: an IME editor action delivered over Binder can race the
+      // removal of this view from the hierarchy. There is no focus to move in that case, so a
+      // plain clearFocus() is enough.
+      val rootViewGroup = rootView as? ViewGroup
+      if (rootViewGroup != null) {
+        val oldDescendantFocusability = rootViewGroup.descendantFocusability
+        rootViewGroup.descendantFocusability = ViewGroup.FOCUS_BLOCK_DESCENDANTS
+        super.clearFocus()
+        rootViewGroup.descendantFocusability = oldDescendantFocusability
+      } else {
+        super.clearFocus()
+      }
     }
     hideSoftKeyboard()
   }