Fix wallpaper picker page TB issue

 - Setup activity title to make TalkBack announce title and response the result after updatnge toolbar title
 video for b/156873798: https://drive.google.com/file/d/1adjMNCCKYTH4lsq_j49vD6coHFNcDMoL/view?usp=sharing
 video for b/157964599: https://drive.google.com/file/d/1CpA-G7CXLMwCOeiu_JP79JpIOjKzPYkX/view?usp=sharing

 Fixes: 156873798
 Fixes: 157964599
 Test: manually

Change-Id: I385197fbaac37578e177a1a65e57ac7a8bddc75d
1 file changed