Drop ESLint and Prettier for Biome

Author: Kocal

assets/src/controller.ts

@@ -7,8 +7,6 @@
  * file that was distributed with this source code.
  */
 
-'use strict';
-
 import { Controller } from '@hotwired/stimulus';
 
 export default class extends Controller {

assets/test/controller.test.ts

@@ -7,8 +7,6 @@
  * file that was distributed with this source code.
  */
 
-'use strict';
-
 import { Application, Controller } from '@hotwired/stimulus';
 import { getByTestId, waitFor } from '@testing-library/dom';
 import { clearDOM, mountDOM } from '@symfony/stimulus-testing';
@@ -33,7 +31,7 @@ const startStimulus = () => {
 };
 
 describe('LazyImageController', () => {
-    let container;
+    let container: HTMLElement;
 
     beforeEach(() => {
         container = mountDOM(`