Fix ANR of SimSlotChangeService

The JobService.onStartJob() is run on main thread, should return in time
instead of wait for job complete, otherwise will cause ANR.

Not wait the job finish, and call jobFinished() when finished to fix
this issue.

Fix: 277031144
Test: Manual check with log that onStartJob() is returned in time
Test: Manual check with log that job is not run in main thread
Change-Id: I1e83363ca87a29fb9424100bf99b3f2d212fd9d0