Camera: ANAPIC AIDL feedback

- In metadata comments, add reference source file where details can be
  found
- Fix grammar in ICameraDeviceSession.aidl comments

Bug: 318762864

Test: build

Change-Id: Id0f88aacd60e9ae444a0f6d4a9dfca67f8d75eaa
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>