Download of KaTeX resources: no error is thrown in case of http error 404

[deining]

As spotted by @fekete-robert:

When downloading KaTeX resources via resources.getRemote, the error checking part when downloading the css/js file doesn't seem to catch if you specify a version number in the config file but it doesn't exist.

ToDo

[x] fixed error in branch main PR #2281.
[x] fixed in PR #2276 via 39fdc87.