Fix splash screen icon on Android 12 (#5565)

* Use Core Splashscreen for splashscreen stuff

* Keep splash screen until activity ready

Ready as in the data inside starting screen is finished showing

* Use custom splash screen exit animation on older android version

* Add splash screen minimum duration to prevent exit jank

* Fix broken AMOLED theme

* Improvements

app/src/main/AndroidManifest.xml

@@ -37,7 +37,7 @@
         <activity
             android:name=".ui.main.MainActivity"
             android:launchMode="singleTop"
-            android:theme="@style/Theme.Splash">
+            android:theme="@style/Theme.Tachiyomi.SplashScreen">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />