web_tree_dynamic_colored_field: Assume that color may not start with 'color_field'

The index at 0 in the following code:
  var colorField = this.arch.attrs.colors.split(';')
  .filter(color => color.trim().startsWith('color_field'))[0]
Was failing on such valid xml:
  <tree string="Buffer monitor"
        colors="red:procure_recommended_qty &gt; 0">

web_tree_dynamic_colored_field/static/src/js/web_tree_dynamic_colored_field.js

@@ -12,10 +12,10 @@ odoo.define('web_tree_dynamic_colored_field', function (require) {
          */
         _renderBody: function () {
             if (this.arch.attrs.colors) {
-                var colorField = this.arch.attrs.colors.split(';')
-                .filter(color => color.trim().startsWith('color_field'))[0]
-                .split(':')[1]
-                .trim();
+                var colorAttr = this.arch.attrs.colors.split(';')
+                    .filter(color => color.trim().startsWith('color_field'));
+                if (colorAttr.length > 0) {
+                    var colorField = colorAttr[0].split(':')[1].trim();
                     // validate the presence of that field in tree view
                     var fieldNames = _(this.columns).map(
                         (value) => { return value.attrs.name; }
@@ -28,6 +28,7 @@ odoo.define('web_tree_dynamic_colored_field', function (require) {
                         this.colorField = colorField;
                     }
                 }
+            }
             return this._super();
         },
         /**