**Backport:** https://codeberg.org/forgejo/forgejo/pulls/6674
- The doctor commands to check the validity of existing usernames and
email addresses depend on functionality that have configurable behavior
depending on the values of the `[service]` settings, so load them when
running the doctor command.
- Resolves#6664
- No unit test due to the architecture of doctor commands.
Co-authored-by: Gusted <postmaster@gusted.xyz>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/6678
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>
Co-committed-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>
