Fix network issue

[HarelM]

Launch Checklist

In case of non 200 response the font and glyphs metadata would return the ajax error object instead of the default value.

Fixes #935

• 935

  • [x] Briefly describe the changes in this PR.
  • [x] Link to related issues.
  • [x] Include before/after visuals or gifs if this PR includes visual changes.
  • [ ] Write tests for all new functionality.
  • [x] Add an entry to CHANGELOG.md under the ## main section.

[HarelM]

We could, I didn't want to change the code a lot ,and only wanted to solve this issue. It can be done as part of a different PR...

[HarelM]

In general, this callback hell should be removed, much like we did for maplibre, but it's not a small change...