[Feature] Cancel custom domain in website hosting

[aFlyBird0]

Search before asking

• [X] I had searched in the issues and found no similar issues.

Feature Request

I can't remove custom domain(go back to generated domain) once I have set.

In addition: I found that first canceling the website hosting and then re-enabling it can achieve a similar effect. (But it doesn't seem quite as elegant.)

Are you willing to submit PR?

• [ ] Yes I am willing to submit a PR!