Fix appearance changed into wrong activity (#34)

the original `AppCompatDelegate.setDefaultNightMode()` is a global setup. when changing the night mode, it will actually call HomeActivity's `onConfigurationChanged`. this pr tries to set night mode to current activity by using the `setLocalNightMode()`

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/appearance/AppearanceModule.kt

@@ -70,12 +70,20 @@ constructor(
   }
 
   public override fun setColorScheme(style: String) {
-    when (style) {
-      "dark" -> AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES)
-      "light" -> AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
-      "unspecified" ->
-          AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM)
+    var nightMode = AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM
+    if (style == "dark") {
+      nightMode = AppCompatDelegate.MODE_NIGHT_YES
+    } else if (style == "light") {
+      nightMode = AppCompatDelegate.MODE_NIGHT_NO
+    } else if (style == "unspecified") {
+      nightMode = AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM
+    }
 
+    val activity = currentActivity
+    if (activity is AppCompatActivity) {
+      (activity as AppCompatActivity).delegate.localNightMode = nightMode
+    } else {
+      AppCompatDelegate.setDefaultNightMode(nightMode)
     }
   }