Pick up current user ID right after registerReiverAsUser

user switch intent broadcast is not sticky and can be missed at start up time.
Pick up current user right after registerReciverAsUser() to avoid
missing broadcast information.

Test: verify setCurrentUserAccount is properly called at start up when
telecom is loaded after user switch. Also do the following local test:
adb shell setprop ril.ecclist 911,122,*911,#911,411.
And then manual test that the bluetooth phone account is chosen for
411 ecall and verify after phone is disconnected, call contacts
are cleared.

Bug: 138684166

Change-Id: I41f0f2f580168043fd80a0a23920a29aebe56ff0