Remove stale comment (#16667)

This happens in `from_settings` instead

crates/uv-auth/src/pyx.rs

@@ -284,7 +284,6 @@ impl PyxTokenStore {
 
     /// Read the tokens from the store.
     pub async fn read(&self) -> Result<Option<PyxTokens>, TokenStoreError> {
-        // Retrieve the API URL from the environment variable, or error if unset.
         if let Some(api_key) = read_pyx_api_key() {
             // Read the API key tokens from a file based on the API key.
             let digest = uv_cache_key::cache_digest(&api_key);