Fix error found during tests (should not occur if odoo database is not rewind)

reception/static/js/reception_index.js

@@ -285,7 +285,9 @@ function group_action() {
  * Remove the grouped orders from the order table to prevent grouping in multiple groups.
  */
 function display_grouped_orders() {
+
     if (table_orders !== null) {
+        var display_something = true;
         $('#groups_items').empty();
         let groups_display_content = "<ul>";
 
@@ -307,7 +309,7 @@ function display_grouped_orders() {
                     }
                 }
             }
-
+            if (group_orders.length > 0) {
                 // Display group
                 document.getElementById("container_groups").hidden = false;
                 let group_row = `<li class="group_line"> Commandes de `;
@@ -332,10 +334,15 @@ function display_grouped_orders() {
 
                 group_row += "</li>";
                 groups_display_content += group_row;
+            } else {
+                display_something = false; // occured making test form local django and preprod (couchdb, odoo)
             }
+        }
+        if (display_something === true) {
             $('#container_groups').show();
             $('#groups_items').append(groups_display_content);
         }
+    }
 }
 
 /**