Revert "Make system bars appearence logic more generic (2/N)"

Revert submission 14880637-b/179251684

Reason for revert:
Broke android.view.inputmethod.cts.NavigationBarColorTest#testDimmingWindow

Reverted Changes:
Id5015014a:Make system bars appearence logic more generic (2/...
I8077020ef:Make system bars appearence logic more generic (1/...

The root cause is expected to be discussed at Bug 191383345.

Bug: 179251684
Bug: 191383345
Fix: 191335315
Test: Manually verified on aosp_coral-userdebug as follows
 1. Have an IME that uses SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR
 2. Show a dialog with FLAG_DIM_BEHIND above the IME
 3. Make sure that navbar icons are optimized for dark background

Change-Id: Id53dfc45551e7975c534d9fa3210db76634c22fb