Cannot update LLM provider access key after initial setup

[AaronMorf]

Type: Bug

Summary

It is not possible to change the API key for an LLM provider after it has been initially configured.

Steps to Reproduce

1. Set up an LLM provider with an API key.
2. Attempt to update or replace the existing API key for that provider.

Expected Behavior

Users should be able to update the API key for any configured LLM provider at any time after the initial setup.

Actual Behavior

There is no way to modify the API key of an already configured LLM provider.

_{Filed via the omadia in-app issue reporter by @AaronMorf.}