RuboCop: Enable RSpec/RepeatedExampleGroup{Body,Description} cops

What does this MR do and why?

In the past, they were automatically disabled by RuboCop due to too many offenses.

Enabling them potentially improves the runtime of some specs so it's worth enabling now.

Contributes to #369268 (closed).

Refs #354328 (comment 870464004)

Done via

rm .rubocop_todo/rspec/repeated_example_group_*
bundle exec rake rubocop:todo:generate[RSpec/RepeatedExampleGroupBody,RSpec/RepeatedExampleGroupDescription]

How to set up and validate locally

bundle exec rubocop --only RSpec/RepeatedExampleGroupDescription --only RSpec/RepeatedExampleGroupBody

MR acceptance checklist

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