Is your feature request related to a problem? Please describe.
We are using Open WebUI as a general solution to manage access to LLMs and RAG applications in our company. Besides the Open WebUI web application, we are using the continue plugin with the following configuration:

"models": [
    {
      "model": "gpt-4o",
      "title": "GPT-4o",
      "apiKey": "sk-...,
      "completionOptions": {},
      "apiBase": "https://openwebui/openai",
      "provider": "openai",
      "requestOptions": {
        "headers": {
            "Content-Type": "application/json"
        }
      }
    },
...

Additionally, we are using pipelines such as the langfuse filter to track the usage. When called via the continue plugin, only the inlet is called. This leaves the response text empty, as it is set in the outlet filter.

Describe the solution you'd like
The inlet as well as the outlet filter of the registered pipelines should be called when using the Open WebUI as an API proxy.

Describe alternatives you've considered
The langfuse filter could be integrated in a general litellm setup, but I think that using inlets and outlets of pipelines in the same way for all chat interactions is a good feature in general.