Mark the EntitlementManager PendingIntents as immutable. am: a36d65da0a

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1557108

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I592fb8876e2c51c5c7c2a043d1a313fe1523ac6a
tree: 05a524f91195cd8bf2cb243efcb8d6a8a95102df
  1. framework/
  2. tests/
  3. Tethering/
  4. .gitignore
  5. OWNERS
  6. PREUPLOAD.cfg
  7. TEST_MAPPING