[automerger skipped] [DO NOT MERGE] Make screenshot error notification PendingIntent immutable am: 1eecc874 am: cc526dd8 -s ours am: d5740f82 -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/13519315

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I321fe6ba2741dc5be6c54acd1c4f7f5b1dc11583