Merge "Bluetooth: Mark unaudited PendingIntents with FLAG_IMMUTABLE" am: 86e190a6e9 am: 841830f845

Original change: https://android-review.googlesource.com/c/platform/packages/apps/Bluetooth/+/1560669

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ibe967e87239a2f7c6dd95b8b6dc98f5750a1985f