[bug][minor] openai_responses_manifold: _emit_error() misuse

[nahoj]

A small error: _emit_error() doesn't take a level parameter so this call raises an exception.
https://github.com/jrkropp/open-webui-developer-toolkit/blob/alpha-preview/functions/pipes/openai_responses_manifold/openai_responses_manifold.py#L856