add default value to profile env variable

[dwentland24]

Motivation/Description of the PR

Assignment of undefined profile to env variable with process.env.profile resulted in a string of "undefined".
This results in mysterious behaviors with code like const profile = process.env.profile || 'chrome'. The env variable cannot evaluate to false as it holds the string undefined.

This PR sets as empty string as default value, so not setting any profile in the command results in an empty string of the profile env variable.

Resolves #3339

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)

[mirao]

Wouldn't be better to return value undefined (of type undefined) instead of '' (an empty string)?
I know that const profile = process.env.profile || 'chrome' works the same way for undefined or ''.
But e.g. if you use if (process.env.profile === undefined) it won't work with your solution.

[dwentland24]

@mirao Yes, you are right.

I would propose to set the env variable only if options.profile is not empty. So we have an unset env variable if options.profile is empty.

[DavertMik]

Thank you!