WIP: Replace jQuery old-style ajax calls with Promise interface
What does this MR do?
Replace jQuery old-style ajax calls with Promise interface (Deferred objects).
Are there points in the code the reviewer needs to double check?
Why was this MR needed?
Old-style jQuery Ajax calls should be removed as jQuery will not be removed in the near future.
Does this MR meet the acceptance criteria?
- Changelog entry added
- Documentation created/updated
- API support added
- Added for this feature/bug
- All builds are passing
- Conform by the merge request performance guides
- Conform by the style guides
Branch has no merge conflicts with
master(if it does - rebase it please)
- Squashed related commits together
What are the relevant issue numbers?
Closes #29105 (closed)