[Wi-Fi] Fix EntityHeader signal strength icon invisible problem

WifiDetailPreferenceController2#onUpdated() triggers each controller
to displayPreference(PreferenceScreen screen) for visibility
updating. However, WifiDetailPreferenceController2 is a much
complex controller which should controll it's components visibility
by itself.

Bug: 152886237
Test: manual visual
      Observe EntityHeader signal strength icon UI display.
Change-Id: I80a8341ae051f21410070a81e01716eb49d2c8da

src/com/android/settings/wifi/details2/WifiNetworkDetailsFragment2.java

@@ -235,6 +235,13 @@ public class WifiNetworkDetailsFragment2 extends DashboardFragment implements
     public void refreshPreferences() {
         final PreferenceScreen screen = getPreferenceScreen();
         for (AbstractPreferenceController controller : mControllers) {
+            // WifiDetailPreferenceController2 gets the callback WifiEntryCallback#onUpdated,
+            // it can control the visibility change by itself.
+            // And WifiDetailPreferenceController2#updatePreference renew mEntityHeaderController
+            // instance which will cause icon reset.
+            if (controller instanceof WifiDetailPreferenceController2) {
+                continue;
+            }
             controller.displayPreference(screen);
         }
     }