[automerger skipped] [DO NOT MERGE] Make PendingIntents in screenshots immutable am: cdd1d2a4fe am: fe43075ab2 -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/13950908

Change-Id: If3a9be05b6c8123e104e1c2996e8f087135a8f51