Resolve OS X autoloading issues with validators

What does this MR do?

Solves the local development problem where this error is shown due to autoloader loading issues

This error pops up when running gdk, rails, or any invocation that loads the application.

Below is example with running a spec to trigger loading environment/application

❯ be rspec ee/spec/features/buy_ci_minutes_notification_dot_spec.rb

An error occurred while loading ./ee/spec/features/buy_ci_minutes_notification_dot_spec.rb.
Failure/Error: API::Validations::Validators::CheckAssigneesCount.prepend_if_ee('EE::API::Validations::Validators::CheckAssigneesCount')

NameError:
  uninitialized constant EE::API::Validations
# ./config/initializers/0_inject_enterprise_edition_module.rb:9:in `prepend_if_ee'
# ./lib/api/validations/validators/check_assignees_count.rb:36:in `<main>'
# ./lib/api/issues.rb:26:in `block (2 levels) in <class:Issues>'
# ./lib/api/issues.rb:32:in `block (2 levels) in <class:Issues>'
# ./lib/api/issues.rb:79:in `block in <class:Issues>'
# ./lib/api/issues.rb:78:in `<class:Issues>'
# ./lib/api/issues.rb:4:in `<module:API>'
# ./lib/api/issues.rb:3:in `<main>'
# ./lib/api/api.rb:143:in `block in <class:API>'
# ./lib/api/api.rb:106:in `<class:API>'
# ./lib/api/api.rb:4:in `<module:API>'
# ./lib/api/api.rb:3:in `<main>'
# (eval):4:in `draw_route'
# ./lib/gitlab/patch/draw_route.rb:32:in `instance_eval'
# ./lib/gitlab/patch/draw_route.rb:32:in `draw_route'
# ./lib/gitlab/patch/draw_route.rb:19:in `draw_ce'
# ./lib/gitlab/patch/draw_route.rb:13:in `draw'
# ./config/routes.rb:220:in `block in <main>'
# ./config/routes.rb:4:in `<main>'
# ./config/environment.rb:5:in `<top (required)>'
# ./spec/spec_helper.rb:10:in `require'
# ./spec/spec_helper.rb:10:in `<top (required)>'
# ./ee/spec/features/buy_ci_minutes_notification_dot_spec.rb:3:in `require'
# ./ee/spec/features/buy_ci_minutes_notification_dot_spec.rb:3:in `<top (required)>'
# ------------------
# --- Caused by: ---
# NameError:
#   uninitialized constant EE::API::Validations
#   ./config/initializers/0_inject_enterprise_edition_module.rb:9:in `prepend_if_ee'

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

/cc @engwan