fix inference sliding_window bug

[donglaiw]

When I first tried to launch training with our updated monai2d_worm.yaml, the run stopped immediately with a configuration error—nothing ever reached the GPU. The problem was triggered by a line like:

inference:
  sliding_window:
    overlap: 0.5

Hydra’s structured config was set up in a way that rejected that value, so setup_config crashed before training could start. After adjusting the config definitions to accept overlap: 0.5, the YAML loads cleanly and training proceeds as expected.