Fixes rubocop warnings in prep for bump of gitlab-style version

What does this MR do and why?

Part of Bump gitlab-styles to v13 (#733) Updates styles within lib/gitlab/qa/scenario to address rubocop warnings

How to set up and validate locally

Edit gitlab-qa.gemspec and set `spec.add_development_dependency 'gitlab-styles', '~> 13'`

$ bundle install
$ bundle exec rubocop lib/gitlab/qa/scenario

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