Fix ListWorkflowRuns OpenAPI response model. (#35026)

Change the OpenAPI response of `ListWorkflowRuns` to `WorkflowRunsList`
like it is supposed to be.

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

services/convert/repository.go

@@ -251,7 +251,7 @@ func innerToRepo(ctx context.Context, repo *repo_model.Repository, permissionInR
 		RepoTransfer:                  transfer,
 		Topics:                        util.SliceNilAsEmpty(repo.Topics),
 		ObjectFormatName:              repo.ObjectFormatName,
-		Licenses:                      repoLicenses.StringList(),
+		Licenses:                      util.SliceNilAsEmpty(repoLicenses.StringList()),
 	}
 }