isAvailable is true by default in dev options

- isAvailable() is defaulted to return true for all developer options
 preferences
 - child controllers should override for custom hiding logic

Bug: 34203528
Test: make RunSettingsRoboTests -j40
Change-Id: I89921f801c25e74bf78d02c55b5f34cf1d464cd0

src/com/android/settings/development/DeveloperOptionsPreferenceController.java

@@ -51,6 +51,16 @@ public abstract class DeveloperOptionsPreferenceController extends
         return false;
     }
 
+    /**
+     * Child classes should override this method to create custom logic for hiding preferences.
+     *
+     * @return true if the preference is to be displayed.
+     */
+    @Override
+    public boolean isAvailable() {
+        return true;
+    }
+
     /**
      * Called when developer options is enabled
      */