Merge "Sharesheet: remove 2 separators, restyle the 3rd." into sc-dev am: 832779a5 am: 96947379

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15377016

Change-Id: Ib98bfd73dd3e5cd09b8621685aa80bf327dd0f0f