Ensure ECCVM polynomial commitments are never points at infinity

[ledwards2225]

From issue made by Zac in aztec-packages: ECCVM prover/verifier uses a workaround for points at infinity that will not work in the recursive setting. Change composer to never produce points at infinity

[ledwards2225]

@zac-williamson Do you know if this is still true/relevant?

[iakovenkos]

They are never points at infinity, because all ECCVM witnesses are masked since AztecProtocol/aztec-packages#12467