Update DetectMultiBackend for tuple outputs 2 (#9275)

* Update DetectMultiBackend for tuple outputs 2

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update

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* Update

* Update

* Update

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

utils/general.py

@@ -813,6 +813,9 @@ def non_max_suppression(prediction,
          list of detections, on (n,6) tensor per image [xyxy, conf, cls]
     """
 
+    if isinstance(prediction, (list, tuple)):  # YOLOv5 model in validation model, output = (inference_out, loss_out)
+        prediction = prediction[0]  # select only inference output
+
     bs = prediction.shape[0]  # batch size
     nc = prediction.shape[2] - 5  # number of classes
     xc = prediction[..., 4] > conf_thres  # candidates