Remove ff dependency (webdriverio#4927)

* remove ff * make puppeteer-ff optionial so --no-optional can be used * removbe import, and require in laucnh function * Update packages/devtools/src/launcher.js Co-Authored-By: Christian Bromann <github@christian-bromann.com> * fix for unit tests Co-authored-by: Christian Bromann <github@christian-bromann.com>

Author: pmerwin

packages/devtools/src/launcher.js

@@ -1,6 +1,5 @@
 import { launch as launchChromeBrowser } from 'chrome-launcher'
 import puppeteer from 'puppeteer-core'
-import puppeteerFirefox from 'puppeteer-firefox'
 import logger from '@wdio/logger'
 
 import { getPages } from './utils'
@@ -58,6 +57,7 @@ async function launchChrome (capabilities) {
 }
 
 function launchFirefox (capabilities) {
+ const puppeteerFirefox = require('puppeteer-firefox')
  const firefoxOptions = capabilities['moz:firefoxOptions'] || {}
  return puppeteerFirefox.launch({
  args: firefoxOptions.args || [],

packages/devtools/tests/__mocks__/puppeteer-firefox.js

@@ -1,3 +1,3 @@
-export default {
+module.exports = {
  launch: jest.fn()
 }