Fix/download before publish

[CelineTrammi]

Ensure download by recipient cannot happen before correspondence is published and not purged

Description

This PR contains logic which ensures that in order to download attachments for a correspondence. The user either has to be a recipient or a sender of the correspondence. Furthermore, if the user is a recipient, the correspondence has to be published and not purged yet.

Other changes:

• A lot of files are changed because of a typo I found in a namespace.
• _getCorrespondenceHelper -> _userClaimsHelper

I am planning on adding validation on scopes and tokens, but realized that would cause more changes and decided to take it in another PR.

Related Issue(s)

• Legge til flere tester for /download endepunktet #247
• Sjekk at Correspondences og Attachment ikke kan hentes ned for mottaker om ikke publisert #181

Verification

• Your code builds clean without any errors or warnings
• Manual testing done (required)
• Relevant automated test added (if you find this hard, leave it and we'll help out)
• All tests run green

Documentation

• User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)