Only fetch steps and trigger for the current workflow version (#15003)

Avoid fetching full steps and trigger for versions that are not the
current version. Because those won't be used anyway. Better for
performances.

Only difficulty was for the `createDraft` mutation. I needed to return
the full created version so I can store it in cache and use it as new
`currentVersion`. Otherwise the current version is considered as
incomplete for a short time, since workflow is fetched separately from
the current version.

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

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

@@ -115,7 +115,11 @@ export class WorkflowVersionWorkspaceService {
       trigger: newWorkflowVersionTrigger,
     });
 
-    return draftWorkflowVersion.id;
+    return {
+      ...draftWorkflowVersion,
+      steps: newWorkflowVersionSteps,
+      trigger: newWorkflowVersionTrigger,
+    };
   }
 
   async updateWorkflowVersionPositions({