There should be two underscores between estimator name and it’s parameters in a Pipeline
logisticregression__C. Do the same for tfidfvectorizer
It is mentioned in the user guide here: https://scikit-learn.org/stable/modules/compose.html#nested-parameters.
See the example at https://scikit-learn.org/stable/auto_examples/compose/plot_compare_reduction.html#sphx-glr-auto-examples-compose-plot-compare-reduction-py