[automerger skipped] [DO NOT MERGE] Make PendingIntents in screenshots immutable am: cdd1d2a4 am: fe43075a -s ours am: aa6e043a -s ours

am skip reason: subject contains skip directive

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

Change-Id: Iac7823ff7321b919017c31604471048ce5359f3a