Copy sharesheet style information into unbundled branch

This restores the semitransparent background and entrance/exit
animations. A bunch of the style stuff is private so it couldn't be
referenced, subsequent CLs will resolve these (left them commented out
for now).

Bug: 202165481
Test: Visual verification
Change-Id: Icd75afde8e0ab3afa2e238c49c526100da86febb
6 files changed