Clean up Sharesheet pinning, add app icon, remove DS pin menu

Remove "App info" item from all long-press menus as it's no
longer needed. Prevent DS targets from showing a long-press
menu. Simplify code surrounding this, in part, for future
migration to a popup menu.

Fixes: 157156399
Test: manual
Change-Id: I3e29e3dd46268cc344dcc93059f2bda1eeef32f1