RSpec/UselessDynamicDefinition: Fix remaining offenses

What does this MR do and why?

This MR fixes all remaining offenses for RSpec/UselessDynamicDefinition and adds reason for inline disables.

It also excludes spec/factories to prevent false positives.

Contributes to #406761 (closed).

How to set up and validate locally

bundle exec rubocop

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.