fix: allow GatherSG to run after workflow updates case

[kevinkim-ogp]

Problem

Plumber’s loop-guard currently uses a simple heuristic: if updatedBy.email is missing, it assumes the change came from an API key/automation and rejects the webhook to avoid infinite loops.

GatherSG’s “Update case → Send webhook” sequence sends:

{
  "updatedBy": {
    "name": "Workflow"
  }
}

No email ⇒ Plumber flags it as automation-originated ⇒ rejected.

Solution

• Allow the Pipe to execute when its updatedBy.name === 'Workflow' and it contains both createdBy.email and createdBy.name to avoid potential infinite loop where API creates case and triggers an instant workflow back to Plumber

Tests

• Create a GatherSG workflow with an update case first then send to webhook. Trigger the workflow and verify that Plumber receives the webhook call.
• Verify that despite this workflow, Plumber can still detect and block infinite loops.