Check access in file.ajax_progress route

kim.pepper → made their first commit to this issue’s fork.

I think it's feasible that anonymous users would be able to see file upload progress, so I don't think it's an access thing. But I do agree we should check if the extension is enabled.

Created a MR.

@kim.pepper

Even if the extension is enabled the message `{"message":"Starting upload...","percentage":-1}` will still appear when no upload process is available.

Can the issue summary be updated to match the standard template?

See there is a test failure so maybe updating that will be enough coverage for the change being made.