lwr: migth raise exception, see !1512. Should we constraint more?

[dannywillems]

          For a follow-up: migth raise exception, see https://github.com/o1-labs/proof-systems/issues/1512. Should we constraint it is greater than 0? Not sure as it would ask to read a huge value in `Fp` `(order - small n)`, which would, probably, be an invalid/unallocated memory location.

Originally posted by @dannywillems in https://github.com/o1-labs/proof-systems/pull/1494#discussion_r1422635287