Sharesheet - Content preview polish

1. Add ripple feedback to clipboard copy even though the sharesheet
disappears really fast and you may not see it.
2. Make sure file icon is gray and not influence by the overlay.
3. Default multiple file sharing to file preview area and not image
preview area when there are mixed file types

Bug: 129979196
Test: Visual inspection
Change-Id: Ia86d418ccaca9a122f00dbc3e9c3b30785fb2abd