Poll on Private Endpoint rule creation to keep Terraform behavior synchronous

[neelshah3]

Changes

https://docs.databricks.com/api/azure/account/networkconnectivity/createprivateendpointrule indicates a CREATING state, but customers expect Terraform to return once creation is successful. This PR ensures Terraform behaves synchronously, even if the API is asynchronous.

Tests

Additional test - Databricks field engineer will test databricks_mws_ncc_private_endpoint_rule creation using this change.

• make test run locally
• relevant change in docs/ folder
• covered with integration tests in internal/acceptance
• using Go SDK
• using TF Plugin Framework
• has entry in NEXT_CHANGELOG.md file

[github-actions]

If integration tests don't run automatically, an authorized user can run them manually by following the instructions below:

Trigger:
go/deco-tests-run/terraform

Inputs:

• PR number: 5325
• Commit SHA: b6caaa81dfbf3663f65e3312308a4be27716962e

Checks will be approved automatically on success.