docs: fix deployment URL for extension RA (#658)

Changes the URL from the VPC landing zone catalog details to the VSI on VPC landing zone details.

The output is a "Configure and deploy" link in the reference architecture in Cloud docs.
https://cloud.ibm.com/docs/secure-infrastructure-vpc?topic=secure-infrastructure-vpc-vsi-ext-ra

Author: SirSpidey

reference-architectures/deploy-arch-ibm-slz-vsi-extension.md

@@ -22,7 +22,7 @@ production: true
 # Value is the URL to land the user in the IBM Cloud catalog details page
 # for the deployable architecture.
 # See https://test.cloud.ibm.com/docs/get-coding?topic=get-coding-deploy-button
-deployment-url: https://cloud.ibm.com/catalog/architecture/deploy-arch-ibm-slz-vpc-9fc0fa64-27af-4fed-9dce-47b3640ba739-global
+deployment-url: https://cloud.ibm.com/catalog/architecture/deploy-arch-ibm-slz-vsi-ef663980-4c71-4fac-af4f-4a510a9bcf68-global
 
 docs: https://cloud.ibm.com/docs/secure-infrastructure-vpc