Convert numpy arrays to lists before saving the evaluation metrics as json (#23268)

* convert numpy array to list before writing to json

per_category_iou and per_category_accuracy  are ndarray in the eval_metrics

* code reformatted with make style

examples/pytorch/semantic-segmentation/run_semantic_segmentation_no_trainer.py

@@ -682,7 +682,9 @@ def main():
             if args.push_to_hub:
                 repo.push_to_hub(commit_message="End of training", auto_lfs_prune=True)
 
-            all_results = {f"eval_{k}": v for k, v in eval_metrics.items()}
+            all_results = {
+                f"eval_{k}": v.tolist() if isinstance(v, np.ndarray) else v for k, v in eval_metrics.items()
+            }
             with open(os.path.join(args.output_dir, "all_results.json"), "w") as f:
                 json.dump(all_results, f)