Allow test-dev2017.txt for val (#14519)

Co-authored-by: UltralyticsAssistant <web@ultralytics.com>

ultralytics/models/yolo/detect/val.py

@@ -68,7 +68,11 @@ class DetectionValidator(BaseValidator):
     def init_metrics(self, model):
         """Initialize evaluation metrics for YOLO."""
         val = self.data.get(self.args.split, "")  # validation path
-        self.is_coco = isinstance(val, str) and "coco" in val and val.endswith(f"{os.sep}val2017.txt")  # is COCO
+        self.is_coco = (
+            isinstance(val, str)
+            and "coco" in val
+            and (val.endswith(f"{os.sep}val2017.txt") or val.endswith(f"{os.sep}test-dev2017.txt"))
+        )  # is COCO
         self.is_lvis = isinstance(val, str) and "lvis" in val and not self.is_coco  # is LVIS
         self.class_map = converter.coco80_to_coco91_class() if self.is_coco else list(range(len(model.names)))
         self.args.save_json |= (self.is_coco or self.is_lvis) and not self.training  # run on final val if training COCO