如何在cascader中设置某个父级选项不可选中，但是依然可以展开下级选项？

[havenothingtosay]

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What problem does this feature solve?

我设置了cascader的changeOnSelect属性为true，想要的效果是，某个一级选项disabled不能被选中作为value，但是其下级的选项依然可以展开被选中，请问该如何实现？

What does the proposed API look like?

我尝试了设置expandTrigger="hover"，但是也无法展开下级选项