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 Output schema was outdated and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-server/src/modules/workflow/workflow-builder/workflow-schema/workflow-schema.workspace-service.ts

@@ -78,11 +78,24 @@ export class WorkflowSchemaWorkspaceService {
         });
       case WorkflowActionType.ITERATOR: {
         return {
-          nextItemToProcess: {
+          currentItem: {
+            label: 'Current Item',
             isLeaf: true,
             type: 'unknown',
             value: generateFakeValue('unknown'),
           },
+          currentItemIndex: {
+            label: 'Current Item Index',
+            isLeaf: true,
+            type: 'number',
+            value: generateFakeValue('number'),
+          },
+          hasProcessedAllItems: {
+            label: 'Has Processed All Items',
+            isLeaf: true,
+            type: 'boolean',
+            value: false,
+          },
         };
       }
       case WorkflowActionType.CODE: // StepOutput schema is computed on serverlessFunction draft execution