docs: mention AppCompatActivity constraint with Expo

Author: hurali97

docs/docs/docs/getting-started/expo.mdx

@@ -88,6 +88,8 @@ override fun onConfigurationChanged(newConfig: Configuration) {
 
 > You can see the demo integration in [Android App](https://github.com/callstack/react-native-brownfield/blob/main/apps/AndroidApp/app/src/main/java/com/callstack/brownfield/android/example/MainActivity.kt) as well
 
+> Using the ComponentActivity does not work with Expo Apps as Expo needs an instance of AppCompatActivity. There is a hard type assertion [here](https://github.com/expo/expo/blob/a2a3c04e5d946182b5aa9e312ef767879119c4bb/packages/expo-modules-core/android/src/main/java/expo/modules/kotlin/AppContext.kt#L292)
+
 4. Build and install the android application 🚀
 
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