Camera service: Update client eviction priorities

Use both oom score and process state for client eviction.
The score will have higher priority over the process state.
This should resolve the state ambiguity when PiP clients
try to connect to exclusive camera resources while
foreground clients are running.

BUG: 34701266
Test: Manual testing, complete CTS Camera package
Change-Id: Ic775b011a20e50f9c0c1c0a4bc1cf7ca75410740