Implement shell commands to allow for CTS testing

Also fixed a bug where AttentionManager was not responding with ATTENTION_FAILURE_CANCELLED when checks are cancelled handled by the manager instead of the service impl. i,e: calling cancelAttentionCheck()

Bug: 123532101
Test: manually verified nothing breaks.
Change-Id: I7ffceb929722a913fcdf8763c1f0b9990dcb3849