Fix undefined in detected tunnels tooltip

Fixes #88245

src/vs/workbench/contrib/remote/browser/tunnelView.ts

@@ -226,7 +226,8 @@ class TunnelTreeRenderer extends Disposable implements ITreeRenderer<ITunnelGrou
 	}
 
 	private renderTunnel(node: ITunnelItem, templateData: ITunnelTemplateData) {
-		templateData.iconLabel.setLabel(node.label, node.description, { title: node.label + ' - ' + node.description, extraClasses: ['tunnel-view-label'] });
+		const label = node.label + (node.description ? (' - ' + node.description) : '');
+		templateData.iconLabel.setLabel(node.label, node.description, { title: label, extraClasses: ['tunnel-view-label'] });
 		templateData.actionBar.context = node;
 		const contextKeyService = this._register(this.contextKeyService.createScoped());
 		contextKeyService.createKey('view', this.viewId);