clobber wom: add onKeyUp callback to SingleKeyRule

- Add a new callback, onKeyUp, in SingleKeyRule for key-up events
that are not processed by long/very-long press.

See comment in go/wear-1pg-button-clobber for the original design idea.

Test: atest WmTests:SingleKeyGestureTests
BUG: 296311571
Change-Id: I8c4907aadee94801a68ad794911a88c2293d49a4