Fix Talkback wrong label announced going from App to Overview

To fix the incorrect title information being spoken after a transition state ends, a new function named getTitle is introduced in the LauncherState. This function provides the correct title for the transition state. The default accessibility label is set to R.string.home_screen. All Apps and Overview states override the getTitle function to ensure the correct accessibility label for their respective states.

Fix: 265892510
Flag: EXEMPT bugfix
Test: Manual with Talkback. With Talkback enabled, navigate from App to Overview.
Change-Id: I96b820f310f8b778a149709bca687a5912386246

src_no_quickstep/com/android/launcher3/uioverrides/states/AllAppsState.java

@@ -52,6 +52,11 @@ public class AllAppsState extends LauncherState {
         return launcher.getString(R.string.all_apps_button_label);
     }
 
+    @Override
+    public int getTitle() {
+        return R.string.all_apps_label;
+    }
+
     @Override
     public int getVisibleElements(Launcher launcher) {
         return ALL_APPS_CONTENT;