[UDFs] Function nodes should support deferral

[QMalcolm]

Housekeeping

• I am a maintainer of dbt-core

Short description

Say I have a model, model_a, that uses a function, function_1. Initially I build the project via dbt build -t prod, that is I build the project against prod. Now I'm doing development and I want my "dev" model_a to use the "prod" function_1. So I use deferral like so dbt run -s model_a --defer --state state_from_prod_run. This fails because model_a fails to find function_1

Acceptance criteria

Functions properly work with deferral

Suggested Tests

Test that functions work with deferral

Impact to Other Teams

N/A

Will backports be required?

No

Context

No response