Refresh summary when update state of preference

TogglePreferenceController won't call refresh summary for
SwitchPreference. Need to call it explicitly in updateState to update
the subtext.

Bug: 150885013
Test: Manually test
Change-Id: I0dafd78d867fc0c66906ee9a2daa7692bb15224b

src/com/android/settings/network/WifiTetherDisablePreferenceController.java

@@ -137,6 +137,7 @@ public final class WifiTetherDisablePreferenceController extends TogglePreferenc
     public void updateState(Preference preference) {
         super.updateState(preference);
         setVisible(mScreen, mPreferenceKey, shouldShow());
+        refreshSummary(preference);
     }
 
     @Override