Make AddressNote’s commitment hiding

[benesjan]

As @critesjosh pointed out we do not currently use randomness in AddressNote. We should do that to make the commitment hiding.

[iAmMichaelConnor]

What was the note's original purpose? Did it need "hiding" for the example contract that it was originally written for? (I.e. was omitting randomness intentional, or accidental?)

[benesjan]

What was the note's original purpose? Did it need "hiding" for the example contract that it was originally written for? (I.e. was omitting randomness intentional, or accidental?)

@iAmMichaelConnor I think it was accidental in this case because it's used in the escrow contract. But even if it was not accidental I think it should contain the randomness because we moved it to aztec.nr for general use.