Require `gl_resository` in internal API spec

Explicitly requiring `Gitlab::GlRepository` in the spec that requires
it makes sure it is correctly prepended with
`EE::Gitlab::Repository`.

Otherwise, if a spec before it autoloaded one of the constants from
within `Gitlab::GlRepository` the module would not be prepended.

ee/spec/requests/api/internal_spec.rb

 # frozen_string_literal: true
 require 'spec_helper'
 
+# Explicitly require `GlRepository` since if it was autoloaded by a previous spec
+# but not really loaded, the `Gitlab::GlRepository` module is not prepended with it's EE counterpart
+require_dependency 'lib/gitlab/gl_repository'
+
 describe API::Internal do
   describe "POST /internal/allowed" do
     context "for design repositories" do