fix: replace some DOM Element method not supported in Salesforce (#84)

* fix: replace some DOM Element method not supported in Salesforce
some methods aren't supported in Salesforce for unknown reasons and it throws some errors like "append function does not exist"

Author: ghiscoding

lib/src/MultipleSelectInstance.ts

@@ -79,7 +79,9 @@ export class MultipleSelectInstance {
       if (hardDestroy) {
         this.options.onHardDestroy();
       }
-      this.elm.before(this.parentElm);
+      if (this.elm.parentElement && this.parentElm.parentElement) {
+        this.elm.parentElement.insertBefore(this.elm, this.parentElm.parentElement!.firstChild);
+      }
       this.elm.classList.remove('ms-offscreen');
       this._bindEventService.unbindAll();