Update workflow version struct (#6716)

We want to avoid the nested structure of active pieces. Steps to execute
will now be separated from the trigger. It will be an array executed
sequentially.

For now a step can only be an action. But at some point it will also be
a branch or a loop

packages/twenty-server/src/modules/workflow/workflow-runner/jobs/run-workflow.job.ts

@@ -38,7 +38,8 @@ export class RunWorkflowJob {
 
     try {
       await this.workflowExecutorWorkspaceService.execute({
-        action: workflowVersion.trigger.nextAction,
+        currentStepIndex: 0,
+        steps: workflowVersion.steps || [],
         payload,
       });