The `/repos/{owner}/{repo}/issues/comments/{id}` API endpoint returns an
`assets` field, but the route handler did not load attachments, thus,
the field was never populated.
This patch fixes that, and adds a test to exercise it. The test fails
without the fix.
This addresses a bug discovered in Codeberg/Community#1607.
Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
(cherry picked from commit fc4f914e71)
9f592578f4