Allows user to assign organization projects to their new issues, using the project sidebar selector, even when repository's projects are disabled.
Moreover, the project sidebar selector is now hidden if no projects (repository-wide + organization-wide) are available.
Fixesforgejo/forgejo#5666
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7999
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
