Correct issue in unflagged code path for separatelyBindToBtIncallService.

The flag check was missing here; as a consequence, when the flag was off,
the BT ICS would get set to type `IN_CALL_SERVICE_TYPE_BLUETOOTH` and
would then be ignored in all the other bind/rebind logic.

Fixes: 323567772
Test: Manual testing for BT behavior.
Test: Re-run unit tests.
Change-Id: I249a1ba5bb1544c61af914c50d60172a0fffb416