Update joomla-field-fancy-select.w-c.es6.js

`this.dataset` isn't working, but `this.select.dataset` is the right call.

Author: thednp

build/media_source/system/js/fields/joomla-field-fancy-select.w-c.es6.js

@@ -126,8 +126,8 @@ window.customElements.define('joomla-field-fancy-select', class extends HTMLElem
       searchPlaceholderValue: this.searchPlaceholder,
       removeItemButton: true,
       searchFloor: this.minTermLength,
-      searchResultLimit: parseInt(this.dataset.maxResults, 10) || 4,
-      renderChoiceLimit: parseInt(this.dataset.maxRender, 10) || -1,
+      searchResultLimit: parseInt(this.select.dataset.maxResults, 10) || 4,
+      renderChoiceLimit: parseInt(this.select.dataset.maxRender, 10) || -1,
       shouldSort: false,
       fuseOptions: {
         threshold: 0.3, // Strict search