Remove deprecation warning for Module#parents

What does this MR do?

Rails 6.0 renamed Module#parents to module_parents. It will be removed in Rails 6.1

References:

• https://edgeguides.rubyonrails.org/6_0_release_notes.html#active-support-notable-changes
• https://github.com/rails/rails/pull/34051

DEPRECATION WARNING: `Module#parents` has been renamed to
`module_parents`. `parents` is deprecated and will be removed in Rails
6.1. (called from model_name at ../ee/app/models/concerns/custom_model_naming.rb:15)