Fix set wrong WFC mode when UE sets SIM PIN lock

Operator specific carrier configuration can only be read after SIM
loaded. When registering roaming network in PIN lock state, it will
use carrier config default value to update wfc roaming mode, thus
leading wrong wfc roaming mode is set.
Don't set wfc mode if sim state isn't loaded.

Bug: 254859190
Test: atest ImsPhoneTest
Test: Manual
Flag: EXEMPT (bug fix)
Change-Id: Ibc43334501b73854385806f0af004e79197f3ad7