Add folder_contents listing in the @listing-custom-fields endpoint

[Abdu-moustafa]

This PR:

• Provides a new slot in the ListingCustomFieldsGet endpoint for folder_contents.
• Excludes dossier assignment from the property sheet when the workspace is active."

For TI-1895

Checklist

Everything has to be done/checked. Checked but not present means the author deemed it unnecessary.

• Changelog entry
• Link to issue (Jira or GitHub) and backlink in issue (Jira)

Only applicable should be left and checked.

• Upgrade-Steps:
  • SQL Operations do not use imported model (see docs)
  • Make it deferrable if possible
  • Execute as much as possible conditionally
  • DB-Schema migration
    • All changes on a model (columns, etc) are included in a DB-schema migration.
    • Constraint names are shorter than 30 characters (Oracle)
• API change:
  • Documentation is updated
  • API Changelog entry (see guide)
  • If breaking:
    • api-change label added
    • #delivery channel notified about breaking change
    • Scrum master is informed
• Bug fixed:
  • Resolved any Sentry issues caused by this bug
• New functionality:
  • for document also works for mail
  • for task also works for forwarding
• Further improvements needed:
  • Create follow-up stories and link them in the PR and Jira issue
• Change could impact client installations, client policies need to be adapted
• New translations
  • All msg-strings are unicode
• Change in schema definition:
  • If missing_value is specified, then default has to be set to the same value

[elioschmutz]

👍 looks good in general

Please separate your commit into two commits. The first commit should add the folder_content listing to the @listing-custom-fields endpoint. The changelog of this commit should be of type .feature and requires an entry in the api-changelog.

The second commit should contain the change where you restrict the assignment slots for teamraum. This commit requires a changelog of type .other without an entry in the api-changelog.

Remember to rename the commit to accurately reflect the changes made in the related commit.

Please, also update the PR title to the main purpose of the PR. Excluding the dossier assignment is just something you have to do that everything works as expected. The main purpose of this PR is to provide the folder_contents listing in the @listing-custom-fields endpoint. The PR description should reflect that and the focus should be on the feature.

[elioschmutz]

👍