I'm trying to add a custom plugin to an editor that I build in Ckeditor online builder.

But I'm getting this error -> CKEditorError: ckeditor-duplicated-modules

Here is my custom plugin, thanks for your help!

import { createDropdown, addListToDropdown} from '@ckeditor/ckeditor5-ui/src/dropdown/utils';
import SplitButtonView from '@ckeditor/ckeditor5-ui/src/dropdown/button/splitbuttonview';
import Collection from '@ckeditor/ckeditor5-utils/src/collection';
import Model from '@ckeditor/ckeditor5-ui/src/model';
import Plugin from '@ckeditor/ckeditor5-core/src/plugin';


export default class InsertDropDown extends Plugin {
 init() {

    const editor = this.editor;
    
    editor.ui.componentFactory.add("InsertDropDown", locale => {
        
        const dropdownView = createDropdown( locale, SplitButtonView );
        dropdownView.buttonView.actionView.set({
            withText: true,
            label: "Campos Dinámicos",
            icon: 'mdi-trash',
            tooltip: true
            });

        const items = new Collection();

        items.add( {
            type: 'button',
            model: new Model( {
                withText: true,
                label: 'Foo'
            } )
        } );

    addListToDropdown( dropdownView, items );
    return dropdownView;
    });
  }
}