Add public constructor for `InputNoteCommitment`

[juan518munoz]

InputNoteCommitment (in crates/miden-protocol/src/transaction/proven_tx.rs) has private fields (nullifier: Nullifier, header: Option<NoteHeader>) and no public constructor. So we should add either of this options to allow deserializing from proto types.

Original discussion on miden-node

[PhilippGackstatter]

Sounds good, let's add an InputNoteCommitment::from_parts_unchecked constructor as suggested in 0xMiden/node#1759 (comment).

[juan518munoz]

from_parts_unchecked

Yeah I forgot about the unchecked suffix, seems adequate for this case, thanks!

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