Get repo assignees and reviewers should ignore deactivated users (#30770) (#30783)

Backport https://github.com/go-gitea/gitea/pull/30770

If an user is deactivated, it should not be in the list of users who are
suggested to be assigned or review-requested.

old assignees or reviewers are not affected.

---
*Sponsored by Kithara Software GmbH*

tests/integration/api_repo_test.go

@@ -671,7 +671,9 @@ func TestAPIRepoGetReviewers(t *testing.T) {
 	resp := MakeRequest(t, req, http.StatusOK)
 	var reviewers []*api.User
 	DecodeJSON(t, resp, &reviewers)
-	assert.Len(t, reviewers, 4)
+	if assert.Len(t, reviewers, 3) {
+		assert.ElementsMatch(t, []int64{1, 4, 11}, []int64{reviewers[0].ID, reviewers[1].ID, reviewers[2].ID})
+	}
 }
 
 func TestAPIRepoGetAssignees(t *testing.T) {