Add reference contracts to extractor metadata

internal/framework/pipeline/runner_test.go

@@ -1269,6 +1269,10 @@ func (extractor *runnerExtractor) SchemaVersion() string {
 	return extractor.schemaVersion
 }
 
+func (extractor *runnerExtractor) ReferenceSlots() []contracts.ReferenceSlot {
+	return nil
+}
+
 func (extractor *runnerExtractor) ManifestMetadata() map[string]any {
 	return extractor.manifestMetadata
 }