[IxModal] 弹窗IxModal 同时设置可拖动与 #header 插槽，控制台会报错

[Ethan-Xie]

• I have searched the issues of this repository and believe that this is not a duplicate.

Reproduction link

https://playground.idux.site/#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

Steps to reproduce

What is expected?

控制台不报错

What is actually happening?

控制台报错

Environment Info

Win10
版本 112.0.5615.138（正式版本） （64 位）

Any additional comments? (optional)

[Ethan-Xie]

弹窗IxModal 设置可拖动下， 如果不设置标题，同时不显示右上角的关闭按钮，控制台会报一样的错误

https://playground.idux.site/#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