Fix note input padding or expected output notes

[bobbinth]

This PR puts note inputs for the expected output notes under a different key so that we can put un-padded note inputs into the advice provider.

This is a temporary fix as note inputs should always be under the same key (the note input commitment). The proper approach would be to store note inputs in the advice map as follows:

note_inputs_commitment |-> [num_inputs, padded_inputs]

[igamigo]

LGTM!