Add model.eval() in TensorBoad graph visualization to avoid BN stats changes (#8629)

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

ultralytics/utils/callbacks/tensorboard.py

@@ -45,6 +45,7 @@ def _log_tensorboard_graph(trainer):
 
         # Try simple method first (YOLO)
         with contextlib.suppress(Exception):
+            trainer.model.eval()  # place in .eval() mode to avoid BatchNorm statistics changes
             WRITER.add_graph(torch.jit.trace(de_parallel(trainer.model), im, strict=False), [])
             LOGGER.info(f"{PREFIX}model graph visualization added ✅")
             return