Improve splash screen to main activity transition

[joshas]

Currently, at least on my phone running Android version 9, the application "cold boot" startup transition from splash screen to main activity is a bit jarring, as splash screen starts fading out to dark background, and main activity starts fading in a bit later. Effect takes less than a second, but creates very noticeable "blink" effect (light background -> dark background -> light background). Switching app to dark theme did not help, as splash screen is white (probably uses global theme). And, yes, I'm one of those stubborn users who are closing the apps and not leaving them running in background.