Correctly update in-progress events when switching uidStates

A in-progress event might have been started multiple times. So to remove
the event and then re-add it we have to temporarily reduce the number
of unfinished started (== the nesting count) to 1 so that finish()
actually removes the event.

Test: atest android.app.appops.cts.AppOpEventCollectionTest#switchUidStateWhileOpsAreRunning
Fixes: 148527247
Change-Id: I40afd83946be202be048c69611f62974a762bdc6