[automerger skipped] [DO NOT MERGE] Make PendingIntents in screenshots immutable am: cdd1d2a4 am: 22945b76 am: f511fd93 -s ours am: 267bd2e0 -s ours

am skip reason: subject contains skip directive

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

Change-Id: I453e25b00af42d0034de6415e43a720bc77976d1