Failing import produces full screen HTML output

[eliasp]

Trying to import the recipe from https://www.oetker.de/rezepte/r/spiralkartoffeln I'm greeted with a fullscreen error, spitting out raw HTML instead of a sensible message like just "Import source is not supported" or so.

See screenshot:

Using:
Nextcloud: 24.0.6
Cookbook: 0.9.15
Cookbook App: 0.7.8

[Leptopoda]

With #171 this won't happen anymore and we just display the status code.

I'll try bringing better error handling into the app