Revert "Add support for taskbar background to wrap around hotseat"

This reverts commit 5dc07d78.

Reason for revert: b/360116669

Bug: 345768019
Change-Id: Id70ceed141e2106f746d4a0e68a09675ba45dd28
Fixes: 360116669
Test: open taskbar, open all apps w/ ime, use ime back button
Flag: com.android.launcher3.enable_scaling_reveal_home_animation