Enable lint enforcement on e2e tests and fix the existing errors (#5229)

* Add `e2e` folder to lint scripts

* Fix or add exceptions to all new linting errors

* fix an oopsie 👀

e2e/playwright-ci.config.js

@@ -2,6 +2,7 @@
 // playwright.config.js
 // @ts-check
 
+// eslint-disable-next-line no-unused-vars
 const { devices } = require('@playwright/test');
 
 /** @type {import('@playwright/test').PlaywrightTestConfig} */