[automerger skipped] Camera: Remove an unused variable mCameraMuteChanged in Camera3Device am: 845f2b3453 -s ours am: 4501fea285 -s ours am: ce8c393a31 -s ours am: 15979c0aad -s ours

am skip reason: Merged-In I0e8dc10cda56a93e4776781ca302aabc4cf4b4da with SHA-1 f2eded320d is already in history

Original change: https://android-review.googlesource.com/c/platform/frameworks/av/+/2696794

Change-Id: Iaf5a954b77ce3a6acaf7b77dba93d7ca983a74b8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>