Skip invoice items with zero total in invoice serializer [WAL-2474]
Skip invoice items with zero total in invoice serializer [WAL-2474]

opennode/waldur-mastermind,opennode/waldur-mastermind,opennode/waldur-mastermind,opennode/nodeconductor-assembly-waldur,opennode/waldur-mastermind,opennode/nodeconductor-assembly-waldur,opennode/nodeconductor-assembly-waldur