Added MLFLOW environment variables for logging metrics within trainig… (#2477)

* Added MLFLOW environment variables for logging metrics within trainign script

* exporting MLFlow env variables from AML env
Co-authored-by: NCheng Li <pistasable@gmail.com>

deepspeed/launcher/runner.py

@@ -27,7 +27,7 @@ from ..utils import logger
 from ..autotuning import Autotuner
 
 DLTS_HOSTFILE = "/job/hostfile"
-EXPORT_ENVS = ['NCCL', 'PYTHON', 'MV2', 'UCX']
+EXPORT_ENVS = ['MLFLOW', 'NCCL', 'PYTHON', 'MV2', 'UCX']
 EXPORT_ENVS += NEBULA_EXPORT_ENVS
 DEEPSPEED_ENVIRONMENT_NAME = ".deepspeed_env"
 DEEPSPEED_ENVIRONMENT_PATHS = [os.path.expanduser("~"), '.']