Merge "Use PendingIntent.FLAG_IMMUTABLE in PendingIntent in NotificationMgr" into qt-dev am: 59d0840be9

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/services/Telephony/+/11256276

Change-Id: I2b653f91d6046c7b737f4cc393db49ab0ae44984