Catch NPE in getServiceStateForSubscriber

ITelephony can enter a bad state with an incorrect SubId and throw an
NPE as shown in the attached bug. This is not an expected error, so a
bugreport will be triggered on userdebug builds on catch.

Test: Local
Bug: 134067547
Change-Id: Ib8f3b69eb3870c3567578aadaee6cf2693526fbd
1 file changed