Show a loader while the group is updating

Signal/src/Loki/View Controllers/EditClosedGroupVC.swift

@@ -241,16 +241,20 @@ final class EditClosedGroupVC : BaseVC, UITableViewDataSource, UITableViewDelega
         guard members != Set(thread.groupModel.groupMemberIds) || name != thread.groupModel.groupName else {
             return popToConversationVC(self)
         }
+        ModalActivityIndicatorViewController.present(fromViewController: navigationController!, canCancel: false) { [weak self] _ in
             try! Storage.writeSync { [weak self] transaction in
                 ClosedGroupsProtocol.update(groupPublicKey, with: members, name: name, transaction: transaction).done(on: DispatchQueue.main) {
                     guard let self = self else { return }
+                    self.dismiss(animated: true, completion: nil) // Dismiss the loader
                     popToConversationVC(self)
                 }.catch(on: DispatchQueue.main) { error in
                     guard let self = self else { return }
+                    self.dismiss(animated: true, completion: nil) // Dismiss the loader
                     self.showError(title: "Couldn't Update Group", message: "Please check your internet connection and try again.")
                 }
             }
         }
+    }
 
     // MARK: Convenience
     private func showError(title: String, message: String = "") {