typo in JS mesh websocket data

src/c3nav/mesh/templates/mesh/fragment_mesh_websocket.html

@@ -11,7 +11,7 @@
 {% if node_names %}
     const node_names = JSON.parse(document.getElementById('node-names').textContent);
 {% endif %}
-{% if node_names %}
+{% if nodes_xyz %}
     const nodes_xyz = JSON.parse(document.getElementById('nodes-xyz').textContent);
     const nodes_distances = {}
 {% endif %}