8839 workflow follow up code step (#8856)

- add readonly mode
- fix falsy stepOutput computation

packages/twenty-server/src/modules/workflow/workflow-builder/workflow-builder.workspace-service.ts

@@ -226,6 +226,7 @@ export class WorkflowBuilderWorkspaceService {
 
     const inputSchema =
       codeIntrospectionService.getFunctionInputSchema(sourceCode);
+
     const fakeFunctionInput =
       codeIntrospectionService.generateInputData(inputSchema);
 
@@ -233,7 +234,7 @@ export class WorkflowBuilderWorkspaceService {
       await serverlessFunctionService.executeOneServerlessFunction(
         serverlessFunctionId,
         workspaceId,
-        fakeFunctionInput,
+        Object.values(fakeFunctionInput)?.[0] || {},
         serverlessFunctionVersion,
       );