Improve wallpaper full preview page TB UX

 - From ag/11910869 (b/157871987), we only control full preview page tab's a11y param, since ag/12067604 changed category/wallpaper list's TB behavior, make full preview page's wallpaper preview pager apply same behavior when bottom sheet expanded (although only a little part be blocked, but once info sheet become bigger, like switch language, the result will similar to ag/11910869)
 video: https://drive.google.com/file/d/1w0nmnwACRvbEEIUaNqQrYIzLN9IQkytG/view?usp=sharing

 Bug: 160284173
 Test: manually

Change-Id: I30807e11914545b2c0d013a18e8fa7904bd04418
2 files changed