Add search_pipeline to path

[tamcv]

Description

Add search_pipeline to path

Issues Resolved

Fix below error when adding search_pipeline to body request:

     Searchkick::InvalidQueryError:
       [400] {"error":{"root_cause":[{"type":"parsing_exception","reason":"Unknown key for a VALUE_STRING in [search_pipeline].","line":1,"col":6513}],"type":"parsing_exception","reason":"Unknown key for a VALUE_STRING in [search_pipeline].","line":1,"col":6513},"status":400}

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[nhtruong]

This line should already allows search_pipeline in the path as a query parameter if you do client.search(search_pipeline: ...) because it's in the ParamRegistry

[tamcv]

Thanks @nhtruong. The problem came from searchkick gem since it haven't supported the search_pipeline param yet.