Restrict languages that can be downloaded for a user/group

[mikefonted]

Describe the bug

A project with Custom access.
A component in that project with multiple languages.
A role with the only permission "Edit strings".
A group with that role, that project, that component and only one language.
A user with that group.

The user still can click on "Download translation files as ZIP file" with all languages.

Related #4519 and #4491

Expected behavior

"Download translation files as ZIP file" with only the language the user has permission to edit.

Server configuration and status

Docker image tag weblate/weblate:4.2.2-2

[nijel]

The user is also able to browse all translations in this case, so the download is consistent with this behavior.

[github-actions]

This issue looks like a support question. We try to answer these reasonably fast, but in case you are looking for faster resolution, please consider purchasing support subscription and make Weblate stronger.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.