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/res/drawable/ic_tachi_splash.xml

@@ -1,12 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <layer-list xmlns:android="http://schemas.android.com/apk/res/android">
-
-    <item android:drawable="@color/splash" />
-
     <item
         android:width="72dp"
         android:height="72dp"
         android:drawable="@drawable/ic_tachi"
         android:gravity="center" />
-
 </layer-list>