Fix build error using RuboCop 1.49+

[koic]

Fixes rubocop/rubocop#11817.

The test code is updated with the following command to resolve the issue:

$ bundle exec rubocop --require rubocop/cop/internal_affairs \
  --only InternalAffairs/RedundantDescribedClassAsSubject,Layout/EmptyLines -a spec

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Run bundle exec rake. It executes all tests and RuboCop for itself, and generates the documentation.

[thomthom]

Oh! Thank you for this PR!

This also answers another think I was curious about - running the InternalAffairs cops on our extension. (I'd just now noticed them in the RuboCop repo.) I'll see if I can hook them up to run with the rest of the checks.

Can I ask some follow up questions to better understand the changes?

I see the gist of the changes is adding , :config to describe and removing subject(:cop) { described_class.new(config) }.
Was this somehow masking the true config that should have been passed to the cops in the tests?
(I'm not super familiar with rspec, I've mostly used it in this project where I used it to more easily mesh with RuboCop. I'm more familiar with MiniTest.)

[koic]

Simple configuration test cases are better replaced like the changes in this PR so that the following shared_context is enabled:
https://github.com/rubocop/rubocop/blob/v1.50.2/lib/rubocop/rspec/shared_contexts.rb#L64-L118