fix issue with image classification use case docs for onnx export

Author: markurtz

src/content/use-cases/image-classification/sparsifying.mdx

@@ -146,5 +146,5 @@ sparseml.image_classification.export_onnx \
     --arch-key resnet50 \
     --dataset imagenet \
     --dataset-path ./data/imagenette-160 \
-    --checkpoint-path sparsification_example/resnet50-imagenette-pruned/framework/model.pth
+    --checkpoint-path sparsification_example/resnet50-imagenette-pruned/training/model.pth
 ```