Playwright: Fixed properties types "waitForNavigation" and "firefox"

[mirao]

Motivation/Description of the PR

• This setup works in JavaScript config:

firefox: {
    firefoxUserPrefs: {
        "browser.cache.disk.max_entry_size": -1,
        "dom.events.testing.asyncClipboard": true
    }
},
waitForNavigation: "networkidle",

, but doesn't work in TypeScript config (3.3.5):

Applicable helpers:

• WebDriver
• Puppeteer
• Nightmare
• REST
• FileHelper
• Appium
• Protractor
• TestCafe
• Playwright

Applicable plugins:

• allure
• autoDelay
• autoLogin
• customLocator
• pauseOnFail
• coverage
• retryFailedStep
• screenshotOnFail
• selenoid
• stepByStepReport
• stepTimeout
• wdio
• subtitles

Type of change

• 🔥 Breaking changes
• 🚀 New functionality
• 🐛 Bug fix
• 📋 Documentation changes/updates
• ♨️ Hot fix
• 🔨 Markdown files fix - not related to source code
• 💅 Polish code

Checklist:

• Tests have been added
• Documentation has been added (Run npm run docs)
• Lint checking (Run npm run lint)
• Local tests are passed (Run npm test)