Stop HfpClientConnectionService on shutdown.

Stop the HfpClientConnectionService when shutting down HfpClientService
via the stopService call rather than startService with an extra.  This
eliminates the chance of the service getting leaked.

Bug: 79258377
Test: Cycle bluetooth adapter; runtest bluetooth
Change-Id: I3c07932d06823ebc7ad081b44879b50ce804bb8a