Align get_model_lineage functions.

[VDFaller]

Non-blocking: I think this should have essentially the same function signature as the other lineage tool: https://github.com/dbt-labs/dbt-mcp/pull/461/files#diff-6d91f0721d8dcde8199de504338811a7063757ec13f32eca508bfbc8b663a54bR390-R396

Originally posted by @DevonFulcher in #420 (comment)