[Feature] Support deferral of semantic models

[ChenyuLInx]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward extension of existing dbt functionality, rather than a Big Idea better suited to a discussion

Describe the feature

We would want to generate the semantic manifest with deferral resolved to make sure the semantic model will point to the deferred node.
This would ensure a consistent experience of developing dbt & semantic model

Describe alternatives you've considered

No response

Who will this benefit?

No response

Are you interested in contributing this feature?

No response

Anything else?

No response

[ChenyuLInx]

I think we need to update merge_from_artifact function to make sure semantic model's node relation gets updated?
Or should we include defer relation inside?
Sort of a tradeoff of whether dbt will resolve the deferral or metric flow.

[ChenyuLInx]

We also could just include the deferal database /schema for each model inside the semantic manifest?

[jtcohen6]

(tbt #8135!)

We also could just include the deferal database /schema for each model inside the semantic manifest?

a.k.a. the defer_relation! However, the defer_relation is added at runtime, not at parsing time. I had a proposal to change this, but I undid it because it needs a bit more consideration of potential downstream impact (e.g. partial parsing) before we implement: 6b63e31

[ChenyuLInx]

I am thinking maybe during runtime we overwrite the original semantic manifest and add this. Need to think a bit more about how to better encapsulate this.