Accessibility improvements

Update content description of custom options and cancel button,
increase touch target size for color options and make the preview 
cards focusable as a group to improve Talkback navigability.


Fixes: 130385136
Fixes: 130393177
Fixes: 130401317
Fixes: 130391709
Change-Id: Ia3b393e9ca676288e064d402761a44753c681a75