feat: update prompt config page (PR 1)

[Goldziher]

This PR updates the prompt config page by doing the following:

1. It removes the testing tab and all the existing testing logic (followup PR will add the wizard instead).
2. It updates the code snippet, making it significantly more complete. The new display has full installation and usage instructions, and it injects the configId and any defined template variables.
3. It fixes issues with the OpenAI testing that I encountered during development. These could be spinned-out into a separate PR, but they are included.

[golansoffer]

In general, I would suggest extracting some of the code (especially rendering-related/JSX) into a standalone component.

Components shouldn't contain a lot of logic or state (similar to writing functions that follow the Single Responsibility Principle). This will help prevent bugs and quirks in the UI while making maintenance much easier.

Regarding useMemo and memo:

useMemo: Use it to cache "expensive" operations or derived state.
If it's possible to extract logic or expensive calculations into a util file, that's even better:
const [value, setValue] = useState();
const [filterTerm, setFilterTerm] = useState("");
const derivedState = useMemo(() => {
return someUtil(...params);
}, [value, filterTerm]);

// utils.ts
function someUtil(...args): K {
// logic
}

https://frontendmastery.com/posts/building-future-facing-frontend-architectures/