Only reuse delegation set of the existing zone if it is created by the same stack

[edwardrf]

Description

Only reuse delegation set of the existing zone if it is created with the same defang:project and defang:stack tags to prevent cd failure of not able to create zones when deploying same domain with different stack

Linked Issues

https://github.com/DefangLabs/defang-mvp/issues/2480

Checklist

• [x] I have performed a self-review of my code
• [x] I have added appropriate tests
• [ ] I have updated the Defang CLI docs and/or README to reflect my changes, if necessary