Lock selenium-webdriver at 4.9.0

What does this MR do and why?

Extension of !120114 (merged)

Fixes broken job in Ruby 2 https://gitlab.com/gitlab-org/gitlab/-/jobs/4255856860

Lock selenium-webdriver at 4.9.0

We can remove this restriction after we drop support for Ruby 2.7 See:

https://github.com/SeleniumHQ/selenium/blob/selenium-4.9.1/rb/CHANGES#L5

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