Bulk apply PendingIntent.FLAG_MUTABLE_UNAUDITED.

We've been working hard to require PendingIntents explicitly declare
if they allow their contents to be mutated or not, and to finish
landing that work this change applies the new FLAG_MUTABLE_UNAUDITED
flag to all remaining code locations until they can be manually
inspected.

Bug: 160794467
Test: manual
Change-Id: I7b9ef5dcd35187facef1ec424589b81f834f23c0