Add databricks_pipeline data source for single pipeline lookup

[Maxcillius]

Changes

This PR introduces a new Terraform data source: databricks_pipeline, allowing users to retrieve details of a single existing pipeline using either its id or pipeline_name.

This provides access to the current live configuration without managing or modifying the pipeline itself. The returned fields currently include:

• id
• state
• run_as_user_name
• cluster_id

This enables safer Terraform usage, e.g. avoiding accidental configuration downgrades.

Example usage:

data "databricks_pipeline" "p" {
  pipeline_name = "Testing"
}

output "pipeline_id" {
  value = data.databricks_pipeline.p.id
}

---

Tests

Validated manually using a real Databricks workspace and pipeline.

Using the custom-built provider:

terraform apply

Output:

pipeline_id = "7d737602-0510-4a5f-9507-ef78d8d3e02d"
state       = "IDLE"
cluster_id  = ""

This verifies:

• name resolution to ID
• successful .Get() request execution
• correct field mapping

---

Checklist

• 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

[alexott]

New data sources should be created with the plugin framework

[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: 5271
• Commit SHA: 960b22c547daa72c6b0e25ff538526b2604603a1

Checks will be approved automatically on success.