Don't use real state machines when testing clean up

Problem: The test in question was instantiating a *real* state machine
to test the in function call to cleanupDevice() when a state machine
calls to remove itself when it disconnects. It was loading a mock into
the map and using the real state machine to eventually invoke the
function it wanted to test. The real state machine was trying to use
real telephony (which should be mocked) and was prone to failing. This
was causing downstream issues where the MMS/SMS DB abstraction couldn't
be created, which threw an exception and left the object null. When
cleanup time happened, mDatabase.cleanup() would throw an NPE, further
hiding the issue.

Solution: Just don't use a real object. Rather then get our mocks in
place for Telephony or changing the code to better handle the Telephony
stack's ability to fail (which are both things we *should* do
eventually), its far easier to test the code path in question with two
mock state machines. There's no reason not to. We get the same coverage
without the errors, and its simpler/less errorprone

Bug: 367386196
Flag: EXEMPT, test change only
Test: atest com.android.bluetooth.mapclient.MapClientServiceTest
Change-Id: I19513f58b0b6e34cb2bd61d77267d2c135ac6809