Failing test: Jest Integration Tests.src/core/server/integration_tests/saved_objects/migrations/group5 - when upgrading to a new stack version if the mappings match (diffMappings() === false) and discardUnknownObjects = false proceeds if there are no unknown documents

Failing test: Jest Integration Tests.src/core/server/integration_tests/saved_objects/migrations/group5 - when upgrading to a new stack version if the mappings match (diffMappings() === false) and discardUnknownObjects = false proceeds if there are no unknown documents #400999