Use non-deprecated method.

getChannel() has been deprecated in favor of getChannelId() and will be
removed soon.

Bug: 135214188
Test: atest com.android.internal.telephony.CarrierServiceStateTrackerTest
Test: atest com.android.internal.telephony.ServiceStateTrackerTest
Change-Id: Ib55299c268d45d4e8ccc6856b9bb4c5caa975aac
2 files changed