Sharesheet - log copy actions.

Since we've promoted Copy to a system action, out of the general list of targets, it's no longer logged with the regular share target logging.

Bug: 140928181
Test: reviewed adb logcat -b event; correct event looks like
sysui_multi_action: [757,1749,758,4,759,1]
Change-Id: I699ffe0fb7c5631c6e8535377ada36a7ce855734