Unregister handler for multi-SIM configuration change

StkAppService can stop itself and new instance of ServiceHandler can be
created whenever the service starts worker thread. Registration of
handler for multi-SIM configuration change should be done after it is
instantiated and unregistration should also be done.

Bug: 148240558
Test: Manual

Change-Id: I21575bb445c5458e345644f465bf2841cd80a3a5
1 file changed