Remove validate_inclusion_of for boolean columns

What does this MR do and why?

Issue: shoulda-matchers: using `validate_inclusion_of`... (#435934 - closed)

Remove validate_inclusion_of for boolean columns as mentioned in https://github.com/thoughtbot/shoulda-matchers/blob/c17c0d71b2a3d33f59996f5fb615929487700598/lib/shoulda/matchers/active_model/validate_inclusion_of_matcher.rb#L62

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Before checking out this branch, run ee/spec/models/remote_development/remote_development_agent_config_spec.rb and notice the warnings from shoulda-matchers.
2. After checking out this branch, run ee/spec/models/remote_development/remote_development_agent_config_spec.rb and notice no warnings from shoulda-matchers.