SystemUI: support black theme for dark mode [1/4]

Also includes squashed change:

Author: Michael Bestas <mkbestas@gmail.com>
Date:   Mon Sep 26 17:29:51 2022 +0300

    fixup! SystemUI: support black theme for dark mode [1/4]

    Fixes color picker

    Change-Id: If29713907a836384c024a4b66ea461acd97f2267

Co-authored-by: Jesse Chan <jc@lineageos.org>
Change-Id: I57cd53de8f2c1e4d445441b514875b6af915b858