AppOpsService: Watch op mode changes when an AppOp restriction dies

On binder death, ensure that any associated watched ops are not left
dangling in an active state.

Test: manual, ops states are now propagated properly after apps are killed
Change-Id: I060d9fabc555e609ad529c612fcb7712f0cea0a6
Merged-In: Ied66c7f49e1c483870048563d08fb57410f004ef