Refresh Wifi AP Config display when config changes

Change-Id: I6fe284355223cbcedd82f95d6415c4d6b660f39f
Fixes: 64757839
Test: robotests
Test: rerun ACTS WifiTetheringTest:test_change_wifi_hotspot_ssid_when_hotspot_enabled

src/com/android/settings/wifi/tether/WifiTetherBasePreferenceController.java

@@ -57,5 +57,8 @@ public abstract class WifiTetherBasePreferenceController extends AbstractPrefere
     public void displayPreference(PreferenceScreen screen) {
         super.displayPreference(screen);
         mPreference = screen.findPreference(getPreferenceKey());
+        updateDisplay();
     }
+
+    public abstract void updateDisplay();
 }