Uncaught (in promise) TypeError: W is not iterable error deleting a Folder from the Tree (test repository and test plan view)

Short Description: Uncaught (in promise) TypeError: W is not iterable error deleting a Folder from the Test Repository Tree (test repository and test plan view).

Steps to Reproduce:

1 - Go to the Test Repository of a project.

2 - Create a Folder and create or add some Tests in it.

3 - Open the left side menu again and click in the "Test Repository" option menu.

4 - Double click on the Folder and delete it.

Actual Results: The screen loads indefinitely with the console error "Uncaught (in promise) TypeError: W is not iterable". The load will stop if the user refreshes the page and the folder gone. If the user does not perform the step 2 (tests in a Folder) or step 3 (click on the left menu), the error seems not to happen.

Expected Results: The folder should be deleted right away.

Note: The same behaviour is shown on the Test Plan view, performing the same steps, but clicking on the Test Plan menu on step 3.