Catch error when dante button isn't found

static/modules/system.js

@@ -129,6 +129,7 @@ class System {
             if (this.pdante != this.dante) { 
                 let button = document.getElementById("toggle-button-dante_active_button");
 
+                if (button !== null) {
                     if (this.dante) { 
                         button.toggle_button.setInactive();
                         console.log("Dante activated");
@@ -139,6 +140,7 @@ class System {
                         main.classList.remove("dante");
                     }
                 }
+            }
             this.pdante = this.dante;
         };