Remove unnecessary azurerm_app_service_virtual_network_swift_connection resource

[jcma-google]

Description

We don't need this resource because we have the virtual_network_subnet_id set in the app resource.

Checklist

General

• [x ] Added the correct label
• [x ] Assigned to a specific person or civiform/deployment-system
• [x ] Created tests which fail without the change (if possible)
• [ x] Performed manual testing (at a minimum run bin/setup without your changes and then bin/deploy with your changes to ensure your changes don't break existing deployments)
• [x ] Extended the README / documentation, if necessary

Instructions for manual testing

If instructions are needed for manual testing by reviewers, include them here.

Issue(s) this completes