Hide App Icons entry when shape and themed icons not available

Show only Themed Icons or only Shapes if only one is available.
Also added more logging when reading options for debugging in the future

Bug: 411007745
Flag: com.android.systemui.shared.new_customization_picker_ui
Test: added unit test for summary
Test: visually verified entry doesn't show up
Change-Id: I5fcc606c60a6918f7254c0c594bfbff22a6acdd5