Bug:PreferredNetworkModePreferenceController.java not being refreshed

Bug: 146594872
Test: make RunSettingsRoboTests ROBOTEST_FILTER=\
PreferredNetworkModePreferenceControllerTest (PASS)

Change-Id: Ic3579e630c1d9422d7105a2d8fb619409a5823d6
Merged-In: Ib5cc06cdbfd2fa70cd115d70337b21500e362da6

src/com/android/settings/network/telephony/PreferredNetworkModePreferenceController.java

@@ -88,6 +88,8 @@ public class PreferredNetworkModePreferenceController extends TelephonyBasePrefe
             Settings.Global.putInt(mContext.getContentResolver(),
                     Settings.Global.PREFERRED_NETWORK_MODE + mSubId,
                     settingsMode);
+            final ListPreference listPreference = (ListPreference) preference;
+            listPreference.setSummary(getPreferredNetworkModeSummaryResId(settingsMode));
             return true;
         }