Prepare to deprecate getHardwareBuffer from TaskSnapshot.(2/N)

To more easily track and manage memory usage of TaskSnapshot object in
a client-side process.

Flag: com.android.window.flags.reduce_task_snapshot_memory_usage
Bug: 238206323
Test: presubmit

Change-Id: I8d7879d9a232aadab97c4953c3b733b81559b6cc