Revert^2 "Recompute color schemes in PlatformTheme when config changes"

This reverts commit 50adc307.

Reason for revert: The regression in b/439984136 is still present after reverting ag/35125268, so undoing the revert.

Fix: 438964734
Bug: 439984136
Change-Id: Ied62e1c0072a6b83ad6687a2e553dd08f9e1a377