Camera2: Invoke saveVideo when mVideoFileDescriptor != null am: 4d60bff648 am: bb8ff8a223

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Camera2/+/18547052

Change-Id: Ic74aa02bd450b4ca00de58348cece06f8688a1c2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>