Add mock key object in tests so content-type detection will pass
Add mock key object in tests so content-type detection will pass

mtekel/digitalmarketplace-admin-frontend,mtekel/digitalmarketplace-admin-frontend,alphagov/digitalmarketplace-admin-frontend,alphagov/digitalmarketplace-admin-frontend,alphagov/digitalmarketplace-admin-frontend,mtekel/digitalmarketplace-admin-frontend,alphagov/digitalmarketplace-admin-frontend,mtekel/digitalmarketplace-admin-frontend