Fixing MainThreadInitializedObject

> Making SafeCloseable implementation mandatory, to prevent leaks during test and preview
> Removing getNoCreate method and defining executeIfCreated to avoid null pointer exceptions
> Fixing sandbox value leaking into main, by Checking sandbox against App context
> Converting sanbox to an interface instead a class

Bug: 335280439
Test: Presubmit
Flag: None
Change-Id: I951dcde871898e745ff6490a1c4f8fd1512888f5

src/com/android/launcher3/provider/RestoreDbTask.java

@@ -526,10 +526,7 @@ public class RestoreDbTask {
         }
 
         logFavoritesTable(controller.getDb(), "launcher db after remap widget ids", null, null);
-        LauncherAppState app = LauncherAppState.getInstanceNoCreate();
-        if (app != null) {
-            app.getModel().forceReload();
-        }
+        LauncherAppState.INSTANCE.executeIfCreated(app -> app.getModel().forceReload());
     }
 
     private static void logDatabaseWidgetInfo(ModelDbController controller) {