Allow to stop running workflow (#15270)

https://github.com/user-attachments/assets/599154e4-8743-471b-b05a-721b635bcf4e

On stoppage:
- if no running steps, mark pending as failed and end the workflow
- if running steps, set as stopping and exit. Going to the next step, as
the workflow is not running anymore, it will naturally stop

packages/twenty-shared/src/workflow/schemas/workflow-run-status-schema.ts

@@ -6,4 +6,6 @@ export const workflowRunStatusSchema = z.enum([
   'COMPLETED',
   'FAILED',
   'ENQUEUED',
+  'STOPPING',
+  'STOPPED',
 ]);