Fix ConcurrentModification with service observers

Ensure that when notifying stale observers, and calling their onChanged
methods, we iterate over a static list copy, as some observers (notably
service observers) remove themselves from the observer list in their
onChanged method.

Fixes: 146349140
Test: Navigate to the Permission settings tab, while some phone
permissions are granted to some apps. The Permission controller summary
should say "Apps using phone" (or include phone in a list of permisions)

Change-Id: I89c35b916ef1c4e00328d017ab82be0f04d95d9f