This still resolves as "business person asks for code, business person gets code, business person says if code is good or not, business person deploys code".
That an LLM or a human is where the code comes from, doesn't make much difference.
Though it does kinda sound like you're assuming all LLMs must develop with Waterfall? That they can't e.g. use Agile? (Or am I reading too much into that?)
> business person says if code is good or not
How do they do this? They can't trust the tests because the tests were also developed by the LLM which is working from incorrect information it received in a chat with the business person.
The same way they already do with humans coders whose unit tests were developed by exactly same flawed processes:
Mediocrely.
Sometimes the current process works, other times the planes fall out of the sky, or updates causes millions of computers to blue screen on startup at the same time.
LLMs in particular, and AI in general, doesn't need to beat humans at the same tasks.