Rename FLASH_CONFIG to match common convention
Rename FLASH_CONFIG to match common convention

mtekel/digitalmarketplace-supplier-frontend,mtekel/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,mtekel/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,mtekel/digitalmarketplace-supplier-frontend