Using generated monochrome icon when actual icon is not available in the full drawable

Also simplifying the bitmap fetching path to return all relevant data in one-call

Bug: 299336510
Test: Verified that the icons are themed during drag and app launch
Flag: ENABLE_FORCED_MONO_ICON
Change-Id: Ib4c457e911e7b5616e8370d111cc68c5d6401fe6