Reload issue when sending webhook to make num comments is right. (#35243)

Fix #35229

---------

Co-authored-by: Giteabot <teabot@gitea.io>

services/issue/comments.go

@@ -80,6 +80,12 @@ func CreateIssueComment(ctx context.Context, doer *user_model.User, repo *repo_m
 		return nil, err
 	}
 
+	// reload issue to ensure it has the latest data, especially the number of comments
+	issue, err = issues_model.GetIssueByID(ctx, issue.ID)
+	if err != nil {
+		return nil, err
+	}
+
 	notify_service.CreateIssueComment(ctx, doer, repo, issue, comment, mentions)
 
 	return comment, nil