Add no-op license helper to CE

Add no-op license helper to CE to make it compatible with EE codebase.
Helper will be overwritten in EE to allow for CE specs to be run under
EE codebase.

https://gitlab.com/gitlab-org/gitlab-ee/issues/6539

ee/spec/support/helpers/ee/license_helpers.rb

 module EE
   module LicenseHelpers
+    extend ActiveSupport::Concern
+
     # Enable/Disable a feature on the License for a spec.
     #
     # Example:
@@ -8,6 +10,8 @@ module EE
     #
     # This enables `geo` and disables `deploy_board` features for a spec.
     # Other features are still enabled/disabled as defined in the license.
+
+    prepended do
       def stub_licensed_features(features)
         existing_features = License::FEATURES_BY_PLAN.values.flatten.map(&:to_sym)
         missing_features = features.keys.map(&:to_sym) - existing_features
@@ -30,4 +34,5 @@ module EE
         ::Gitlab::CurrentSettings.update!(check_namespace_plan: true)
       end
     end
+  end
 end

spec/services/quick_actions/interpret_service_spec.rb

@@ -16,7 +16,6 @@ describe QuickActions::InterpretService do
 
   before do
     stub_licensed_features(multiple_issue_assignees: false)
-
     project.add_developer(developer)
   end
 

spec/spec_helper.rb

@@ -68,6 +68,7 @@ RSpec.configure do |config|
     metadata[:type] = match[1].singularize.to_sym if match
   end
 
+  config.include LicenseHelpers
   config.include ActiveJob::TestHelper
   config.include ActiveSupport::Testing::TimeHelpers
   config.include CycleAnalyticsHelpers

spec/support/helpers/license_helper.rb

+# frozen_string_literal: true
+
+# Placeholder module for EE implementation needed for CE specs to be run in EE codebase
+module LicenseHelpers
+  def stub_licensed_features(features)
+    # do nothing
+  end
+end
+
+LicenseHelpers.prepend(EE::LicenseHelpers)