fix: modified the _set_value function logic based on the mode of MMenu

[xiaonuoAndy]

modify logic:

1. mode is Cascader, value from long path
2. mode is Exclusive , value form action.get('value')
3. mode is Single, value form [action.get('value')]

[loonghao]

读了下上下文 感觉这里可以直接简化成这样

act_value = self.property("cascader") and act.property("long_path") or act.property("value")

[loonghao]

你看看如果是修改成这样是否也能符合预期？

Suggested change

	selected_data = ['/'.join(map(str, value))]
	else:
	if self._action_group.isExclusive():
	selected_data = [value]
	else:
	selected_data = value
	selected_data = ['/'.join(map(str, value))]
	else:
	selected_data = [value]

[muyr]

把 "/" 改为 self.property("separator") 吧