Fixed GbaServiceTest on HSUM devices

Fixed by always binding to the overridden Gba package for
the current user.

Also fixed the unit test that takes 17 seconds by using
the existing telephony testable looper infrastructure
so the running time is down to few milliseconds.

Fix: 369560559
Test: atest GbaServiceTest
Flag: EXEMPT test fix
Change-Id: I0265ae002188c706aed6765af5c4ed9e7f68213d