fix vis regist (#1798)

mmdet3d/engine/__init__.py

+# Copyright (c) OpenMMLab. All rights reserved.
+from .hooks import Det3DVisualizationHook
+
+__all__ = ['Det3DVisualizationHook']

mmdet3d/engine/hooks/__init__.py

 # Copyright (c) OpenMMLab. All rights reserved.
-from visualization_hook import Det3DVisualizationHook
+from .visualization_hook import Det3DVisualizationHook
 
 __all__ = ['Det3DVisualizationHook']

mmdet3d/utils/setup_env.py

@@ -68,6 +68,7 @@ def register_all_modules(init_default_scope: bool = True) -> None:
             Defaults to True.
     """  # noqa
     import mmdet3d.datasets  # noqa: F401,F403
+    import mmdet3d.engine  # noqa: F401,F403
     import mmdet3d.evaluation.metrics  # noqa: F401,F403
     import mmdet3d.structures  # noqa: F401,F403
     import mmdet3d.visualization  # noqa: F401,F403