added pipeline dynamic filters

[tachyean]

By defining a RAG retrieval pipeline, the filters can be defined only once when the MilvusEmbeddingRetriever class instance is created. If you need to query a different file for example using the same pipeline is not possible unless you allow changing the filters at run time.

Eg:

pipeline.run(
    {
        "retriever": {"filters": {"field": "file_path", "operator": "==", "value": "someDocument.txt"}},
        ...
    }
)

This is what i am trying to fix with this commit. I found no other way to achieve this. 😅