square.onVendorCreated subscribes to vendor.created for the selected seller. It requires VENDOR_READ.
Example
automations/square-on-vendor-created.automation.ts
Event
Published when a vendor is created by calling CreateVendor or BulkCreateVendors , as well as using the Square Dashboard. The signal resolves to the officialSquare.VendorCreatedEvent payload with type narrowed to vendor.created.