[proto][tests] Fix missing extra_dims in cxcywh (#6906)

test/prototype_common_utils.py

@@ -373,8 +373,8 @@ def make_bounding_box_loader(*, extra_dims=(), format, spatial_size="random", dt
             h = randint_with_tensor_bounds(1, height - y)
             parts = (x, y, w, h)
         else:  # format == features.BoundingBoxFormat.CXCYWH:
-            cx = torch.randint(1, width - 1, ())
-            cy = torch.randint(1, height - 1, ())
+            cx = torch.randint(1, width - 1, extra_dims)
+            cy = torch.randint(1, height - 1, extra_dims)
             w = randint_with_tensor_bounds(1, torch.minimum(cx, width - cx) + 1)
             h = randint_with_tensor_bounds(1, torch.minimum(cy, height - cy) + 1)
             parts = (cx, cy, w, h)