fix(MultiSelect): add missing name attribute to native select element

Author: mrholek

js/src/multi-select.js

@@ -409,6 +409,10 @@ class MultiSelect extends BaseComponent {
       this._updateSearch()
     }
 
+    if (this._element.id) {
+      this._element.setAttribute('name', `multi-select-${this._element.id}`)
+    }
+
     this._createOptionsContainer()
     this._hideNativeSelect()
     this._updateOptionsList()