Sandbox changes for use in UXR prototype.

- "All Set" screen doesn't show after Home/Overview/Back tutorials.
 - X button in top left is hidden (we'll want to move this to the
   feedback view).
 - Feedback pops in and out from the top of the screen.
 - Hand animation is replaced by video feedback at start and after
   incorrect gesture.
 - Back tutorial goes left then right, in order to match video.
 - Updated strings and marked translatable (UX-reviewed already).
 - Added Chinese translations.
 - Many other things.

Test: Manual
Change-Id: I126a3ea0dad645014fab9cdee2ed19e06a8a56e9

src/com/android/launcher3/settings/DeveloperOptionsFragment.java

@@ -276,7 +276,7 @@ public class DeveloperOptionsFragment extends PreferenceFragmentCompat {
         launchBackTutorialPreference.setOnPreferenceClickListener(preference -> {
             startActivity(launchSandboxIntent.putExtra(
                     "tutorial_steps",
-                    new String[] {"RIGHT_EDGE_BACK_NAVIGATION"}));
+                    new String[] {"LEFT_EDGE_BACK_NAVIGATION"}));
             return true;
         });
         sandboxCategory.addPreference(launchBackTutorialPreference);