Update the splash screen logic for the Godot app template

Due to limitations to the splash screen introduced in Android 12, the splash screen logic is updated to the same logic as used on other platforms, i.e: the splash screen is rendered by the Godot engine instead of the Android runtime.

platform/android/java/app/res/drawable/splash_drawable.xml

@@ -1,12 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
-
-	<item android:drawable="@drawable/splash_bg_color" />
-
-	<item>
-		<bitmap
-				android:gravity="center"
-				android:filter="false"
-				android:src="@drawable/splash" />
-	</item>
-</layer-list>

platform/android/java/app/res/values/themes.xml

@@ -3,8 +3,17 @@
 
 	<style name="GodotAppMainTheme" parent="@android:style/Theme.Black.NoTitleBar"/>
 
-	<style name="GodotAppSplashTheme" parent="@android:style/Theme.Black.NoTitleBar.Fullscreen">
-		<item name="android:windowBackground">@drawable/splash_drawable</item>
-		<item name="android:windowLayoutInDisplayCutoutMode">shortEdges</item>
+	<style name="GodotAppSplashTheme" parent="Theme.SplashScreen">
+		<!-- Set the splash screen background, animated icon, and animation
+   duration. -->
+		<item name="android:windowSplashScreenBackground">@mipmap/icon_background</item>
+
+		<!-- Use windowSplashScreenAnimatedIcon to add a drawable or an animated
+			 drawable. One of these is required. -->
+		<item name="windowSplashScreenAnimatedIcon">@mipmap/icon_foreground</item>
+
+		<!-- Set the theme of the Activity that directly follows your splash
+		screen. This is required. -->
+		<item name="postSplashScreenTheme">@style/GodotAppMainTheme</item>
 	</style>
 </resources>