Camera: Improve docs for session parameters am: 622e3bd686 am: e9907fc80a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/24621696

Change-Id: Id96c8112b276067b33fb708e817aae5aae5c4889
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>