Use variables within Iterators (#14604)

Variables were not working properly. Output schema was outdated and
parent steps were not calculated properly.

Before


https://github.com/user-attachments/assets/b070c1ff-41dd-4ea0-a590-25bb39027456

After


https://github.com/user-attachments/assets/baa43e69-0e7c-4697-8812-3ce523efba13

packages/twenty-front/src/modules/workflow/workflow-variables/hooks/useAvailableVariablesInWorkflowStep.ts

@@ -25,9 +25,10 @@ export const useAvailableVariablesInWorkflowStep = ({
   );
   const flow = useFlowOrThrow();
   const steps = flow.steps ?? [];
+  const currentStep = steps.find((step) => step.id === workflowSelectedNode);
 
-  const previousStepIds: string[] = isDefined(workflowSelectedNode)
-    ? getPreviousSteps(steps, workflowSelectedNode).map((step) => step.id)
+  const previousStepIds: string[] = isDefined(currentStep)
+    ? getPreviousSteps({ steps, currentStep }).map((step) => step.id)
     : [];
 
   const availableStepsOutputSchema: StepOutputSchemaV2[] = useRecoilValue(