Remove cancel listeners from pending intent alarms

The cancel listeners are created per PendingIntent instance and were
spamming the callback list stored inside PendingIntentRecord. In cases
where there is even a single live PendingIntent backed by this
PendingIntentRecord, all PendingIntent instances backed by this
PendingIntentRecord for which a callback was ever registered will leak.

Test: atest FrameworksMockingServicesTests:\
com.android.server.am.PendingIntentControllerTest
atest FrameworksMockingServicesTests:\
com.android.server.AlarmManagerServiceTest

Bug: 143091024
Change-Id: I65df12da0c437064e6e3719911926738c677c4eb