Replace `mlflow` with `mlflow-skinny` to avoid installing unnecessary dependencies.

• Please check this box if this contribution uses AI-generated content (including content generated by GitLab Duo features) as outlined in the GitLab DCO & CLA. As a benefit of being a GitLab Community Contributor, you receive complimentary access to GitLab Duo.

mlflow-skinny is a lightweight MLflow package without SQL storage, server, UI, or data science dependencies.

See https://mlflow.org/docs/latest/quickstart_drilldown/