don't preload videos, try to fix Leaflet CSP errors

layouts/_default/single.html

@@ -24,7 +24,7 @@
        <script>
           var map = L.map('map').setView([55, -3], 13);
 
-          L.tileLayer('https://tile.openstreetmap.org/{z}/{x}/{y}.png', {
+          L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
               maxZoom: 19,
               attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a>'
           }).addTo(map);