Don't activate VVM if carrier config changed without signal

CARRIER_CONFIG_CHANGED can be spammed during low signal condition,
which might repeatedly launch TaskSchedulerService and causes a long
wakelock.

In this CL, the activation task will not be queued if the cellular
signal is not available during the change.

Bug: 33693814
Change-Id: I0ed8e62b19589e4dfb47aafcf49a14448418feb4
Fixes: 33693814
Test: N/A
1 file changed