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

spec/services/quick_actions/interpret_service_spec.rb

@@ -15,6 +15,7 @@ describe QuickActions::InterpretService do
   let(:service) { described_class.new(project, developer) }
 
   before do
+    stub_licensed_features(multiple_issue_assignees: false)
     project.add_developer(developer)
   end
 

spec/spec_helper.rb

@@ -66,6 +66,7 @@ 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