File upload xml mimetype not validated correctly

[magnusrf]

Description of the bug

When a user is trying to upload a file with mimetype text/xml it validates as not correct

this error is also seen

Steps To Reproduce

1. https://pat.apps.tt02.altinn.no/pat/correspondence
2. Go to "Attachments"
3. Choose "sequence list"
   3 upload xml file

Additional Information

No response

[ivarne]

Altinn.FileAnalyzers depends on https://github.com/MediatedCommunications/Mime-Detective witch as the name suggests tries to figure out what mime type a file might be, and not assert that it isn't what it is claimed to be.

It works fairly well with images and other binary formats (because they usually start with a unique HEADER byte per file format), but text based formats have issues.

It's a lot of work to make FileAnalyzers right, so my current recommendation would be not ut use it when text based formats is to be expected.