Model Registry: Support load_model for runs

What does this MR do and why?

This MR adds support for downloading artifacts from a Run using MLflow. See below example on how to load the run

import os
import mlflow.pyfunc
import mlflow

os.environ['MLFLOW_TRACKING_TOKEN'] = 'glpat-<redacted>'
os.environ['MLFLOW_TRACKING_URI'] = "http://127.0.0.1:3000/api/v4/projects/7/ml/mlflow/"

mlflow.set_tracking_uri(os.environ['MLFLOW_TRACKING_URI'])

mlflow.pyfunc.load_model(f"runs:/6ac0ba4c-39fb-4a41-b469-fef2bb108105/", dst_path="models")

This downloads the artifacts in a local directory called models.

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Related to #509595 (closed)