Fix PhoneSwitcher singleton not being initialized

Fixes the following exception:

  java.lang.NullPointerException: Attempt to invoke virtual method 'void com.android.internal.telephony.PhoneSwitcher.trySetOpportunisticDataSubscription(int, boolean, com.android.internal.telephony.ISetOpportunisticDataCallback)' on a null object reference

Issue: FP2A10-168
Test: atest -vv android.telephony.cts.SubscriptionManagerTest#testSetPreferredDataSubscriptionId
Fixes: d8659ce32 ("Start using inject framework support")
Change-Id: I33a3971d26f5fa5def5afc0eb3d395d3cb143e4c
1 file changed