Update preset color option icon mapping

Update how color option icons appear to make sure there is adequate
contrast and to match the spec.

Flag: com.android.systemui.shared.new_customization_picker_ui
Test: build & install different themes stub packages
Test: manually verified color options with flag on and off
Bug: 399098020
Change-Id: I7bb48635a5a6ad715707fc22de1c2e8117b0f728