Remove unused SwitchBar

Only used in tests, so also migrate the tests.

Bug: 306658346
Test: manual - on bluetooth
Test: m RunSettingsRoboTests
Change-Id: Id2b010c1d9c32abe21dcc8765e9446fc4f7a5b25

src/com/android/settings/development/graphicsdriver/GraphicsDriverGlobalSwitchBarController.java

@@ -43,16 +43,13 @@ public class GraphicsDriverGlobalSwitchBarController
                    GraphicsDriverContentObserver.OnGraphicsDriverContentChangedListener,
                    LifecycleObserver, OnStart, OnStop {
 
-    private final Context mContext;
     private final ContentResolver mContentResolver;
-    @VisibleForTesting
-    SwitchWidgetController mSwitchWidgetController;
+    private final SwitchWidgetController mSwitchWidgetController;
     @VisibleForTesting
     GraphicsDriverContentObserver mGraphicsDriverContentObserver;
 
     GraphicsDriverGlobalSwitchBarController(
             Context context, SwitchWidgetController switchWidgetController) {
-        mContext = context;
         mContentResolver = context.getContentResolver();
         mGraphicsDriverContentObserver =
                 new GraphicsDriverContentObserver(new Handler(Looper.getMainLooper()), this);