Bug 1844386 - Only use splash screen animation for SDK 31+

app/src/main/res/drawable-v23/splash_screen.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item
+        android:drawable="@mipmap/ic_launcher_round"
+        android:width="160dp"
+        android:height="160dp"
+        android:gravity="center" />
+</layer-list>

app/src/main/res/values-v24/styles.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<resources>
+    <style name="SplashScreen" parent="SplashScreenThemeBase">
+        <item name="windowSplashScreenAnimatedIcon">@drawable/animated_splash_screen</item>
+        <!-- Splash screen is animated to maximum 12 seconds -->
+        <item name="windowSplashScreenAnimationDuration">12000</item>
+    </style>
+</resources>

app/src/main/res/values/styles.xml

@@ -4,12 +4,11 @@
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
 <resources xmlns:tools="http://schemas.android.com/tools">
 
-    <style name="SplashScreen" parent="Theme.SplashScreen">
+    <style name="SplashScreen" parent="SplashScreenThemeBase"/>
+
+    <style name="SplashScreenThemeBase" parent="Theme.SplashScreen">
+        <item name="windowSplashScreenAnimatedIcon">@drawable/splash_screen</item>
         <item name="windowSplashScreenBackground">@color/fx_mobile_layer_color_1</item>
-        <item name="windowSplashScreenIconBackgroundColor">@color/fx_mobile_layer_color_1</item>
-        <item name="windowSplashScreenAnimatedIcon">@drawable/animated_splash_screen</item>
-        <!-- Splash screen is animated to maximum 12 seconds -->
-        <item name="windowSplashScreenAnimationDuration">12000</item>
         <item name="postSplashScreenTheme">@style/NormalTheme</item>
     </style>