Saving domain on edit page may result in undesired domain sort order change

Problem/Motivation

Domains can be sorted on the /admin/config/domain page and doing this results in weights being assigned. In my use case, I currently have 5 domains. Sorting the domains using the draggable table and saving sets weight values from -10 to -6 on the domains. If I now edit a domain by following the edit link, the weight select is populated with '-6' as the delta is calculated as the number of domains +1.

Saving the domain results in the sort order being corrupted as the edited domain will always be pushed to the bottom of the list.

Proposed resolution

The delta calculated in domain/domain/src/DomainForm.php should be based on the currently assigned maximum absolute value +1 so, in my case, the delta should be 11 giving a range from -11 to +11