Function unset_architect_llm_vendor_secret 

pub fn unset_architect_llm_vendor_secret(
    config: &DbBackendConfig,
    adapter: &dyn DatabaseOperations,
    schema: &AppSchema,
    vault_path: &Path,
    root_key_file: &Path,
    llm_vendor_id: &str,
) -> Result<ArchitectVaultResult, AgentErrorKind>

Removes one Architect LLM vendor secret and clears its LLM vendor connection reference.