Show Styles & Wallpaper in Settings

Show "Styles & Wallpaper" in Settings based on whether the ThemePicker
component is availalable. Also update dashboard summary for display.

Bug: 129874298
Test: m RunSettingsRoboTests
Change-Id: Id7e0bb9cbc689bb9e637919a10a7d1006397afab

tests/robotests/src/com/android/settings/testutils/shadow/SettingsShadowResources.java

@@ -12,6 +12,7 @@ import androidx.annotation.ArrayRes;
 import org.robolectric.annotation.Implementation;
 import org.robolectric.annotation.Implements;
 import org.robolectric.annotation.RealObject;
+import org.robolectric.annotation.Resetter;
 import org.robolectric.shadows.ShadowResources;
 import org.robolectric.util.ReflectionHelpers.ClassParameter;
 
@@ -40,6 +41,7 @@ public class SettingsShadowResources extends ShadowResources {
         overrideResource(resId, value);
     }
 
+    @Resetter
     public static void reset() {
         sResourceOverrides.clear();
     }