Added configuration for VT downgrade/tear down when data disabled

Added a new flag that allows carriers to ignore data disabled
(e.g. data reaches limit or user disables data) so VT calls
will not be downgraded/torn down and VT service will not be
disabled.

Test: telephony unit tests
bug: 32880745
Change-Id: I57a7c4f5304ced4ac25cba9329f30dfa912bc662
diff --git a/src/com/android/phone/CallFeaturesSetting.java b/src/com/android/phone/CallFeaturesSetting.java
index 111e263..b5e8026 100644
--- a/src/com/android/phone/CallFeaturesSetting.java
+++ b/src/com/android/phone/CallFeaturesSetting.java
@@ -284,7 +284,9 @@
 
         if (ImsManager.isVtEnabledByPlatform(mPhone.getContext()) &&
                 ImsManager.isVtProvisionedOnDevice(mPhone.getContext()) &&
-                mPhone.mDcTracker.isDataEnabled(true)) {
+                (carrierConfig.getBoolean(
+                        CarrierConfigManager.KEY_IGNORE_DATA_ENABLED_CHANGED_FOR_VIDEO_CALLS)
+                        || mPhone.mDcTracker.isDataEnabled(true))) {
             boolean currentValue =
                     ImsManager.isEnhanced4gLteModeSettingEnabledByUser(mPhone.getContext())
                     ? PhoneGlobals.getInstance().phoneMgr.isVideoCallingEnabled(