Tasks sort delete fix (#8526)

* Fixed task sorting

* Add sync when group task is deleted

* Added sync when user tasks reorder

* Abstracted show logic and removed task grouping from group page

* Fixed scope typo

* Localized the default challenge short name

* Removed default shortName

* Fixed test for challenge shortName

test/api/v3/integration/challenges/POST-challenges_challengeId_leave.test.js

@@ -117,9 +117,6 @@ describe('POST /challenges/:challengeId/leave', () => {
       });
 
       expect(testTask).to.not.be.undefined;
-      expect(testTask.challenge).to.eql({
-        shortName: 'None',
-      });
     });
   });
 });