Pull request #9304 fixed issue #9293 by adding **predict_params to predict method of Pipeline, but predict_proba was not changed and still only takes one parameter. I don't see why predict_proba (and also predict_log_proba) shouldn't also be updated in the same fashion, but I may be missing something.
Also as a related change, fit_predict also has this inconsistency, but in this case it's harder to do as cleanly (as there is already **fit_params passed as kwargs) - but maybe adding predict_params just as a normal, optional dict would be justified?