Launch WfcActivation with subscription ID

For multi SIM project, need to have subscription ID information in the
intent for launching WFC activation activity.

Bug: 112826472
Test: manual test
Change-Id: I9f470c014054efa612c87ff16e574fc9fd286b3d

src/com/android/settings/wifi/calling/WifiCallingSettingsForSub.java

@@ -398,6 +398,7 @@ public class WifiCallingSettingsForSub extends SettingsPreferenceFragment
         // Build and return intent
         Intent intent = new Intent();
         intent.setComponent(componentName);
+        intent.putExtra(SubscriptionManager.EXTRA_SUBSCRIPTION_INDEX, mSubId);
         return intent;
     }