Revert "Rename CameraStateMonitor to simplify interface extraction."

This reverts commit d84b3e5a.

Reason for revert: Duplicating the whole CameraStateMonitor into another class is not necessary - only the delayed processing is different. Removing this as we don't need this interface.

Bug: 380840084
Change-Id: Id8640cee1b22197d9c7e2da7db49c24902d08380