Upgrade to RuboCop 1.50.2

This MR upgrades RuboCop to 1.50.2. This upgrade is needed to add rubocop-erb (which requires >= 1.45.0)

It also upgrade RuboCop RSpec to 2.20.0 because it's being updated on gitlab-org/gitlab anyway due to ~> 2.18. Fix offenses as well.

• https://my.diffend.io/gems/rubocop/1.43.0/1.50.2 - https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md#1502-2023-04-17
• https://my.diffend.io/gems/rubocop-rspec/2.18.1/2.20.0 - https://github.com/rubocop/rubocop-rspec/blob/master/CHANGELOG.md#2200-2023-04-18

Fixed offenses

5  InternalAffairs/LocationExpression
3  RSpec/ContextWording
1  InternalAffairs/RedundantSourceRange
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9  Total in 8 files

Impact gitlab-org/gitlab

See gitlab-org/gitlab!118399 (closed)