Error and inconcistency when deleting form element after reordering

Starting to work on this issue.

I have created the MR. I worked on it for so much time. Initially, I thought I could just add the validation and then I see that element validations are different than form validation itself and event that didn't worked because there was not identifier to know if the element weight is changed.

The better and I think only approach to solve this was doing some checking on the frontend side using the JS.

I am adding the warning message when an element is dragged to save the form before making any changes. Even if user ignores that warning and just click on delete action link for the element then I disabled the delete button and show the same message as error in the dialog modal.