Revert "Add the FLAG_IMMUTABLE flag for creating a PendingIntent"

This reverts commit 334968c113aca1e0c968223bd75a3b2ad643d135.

Reason for revert: Bug: 170280415

Change-Id: Idaa269406d6c1609c75f0dfba1f7fa9daf979101
(cherry picked from commit ee1360f13c37a6d86e7806250e3b2489e7dbd8de)
8 files changed