Set connection details in selenium-standalone properly

[christian-bromann]

Proposed changes

Fixes an issue where setting the @wdio/selenium-standalone-server would start the session but fails with every consecutive request. This happens because we would usually default to WebDriver default connection values http://localhost:4444. In v6 we don't do this anymore since it is possible to run tests straight with Puppeteer.

As solution the service will implicitly set default WebDriver connection values if it is being used (for all capabilities).

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• I have added proper type definitions for new commands (if appropriate)

Further comments

n/a

Reviewers: @webdriverio/project-committers