Verifiers should notify coordinator of corrupted chunks, and coordinator should roll them back accordingly

[jules]

[apruden2008]

Currently, the verifier returns an error such as this:

Sep 27 19:58:50 a-verifier1 setup1-verifier[1179]: thread '<unnamed>' panicked at 'could not check ratios for tau_g1 elements: ZexeSerializationError(InvalidData)', /home/aleo/buil d/aleo-setup/phase1/src/verification.rs:307:30

in the event that a contribution is malformed or corrupted. Currently, the verifier panics and does not do error handling. Instead, we need to ensure that the verifier handles the error by sending to the coordinator, which will re-assign that chunk to the contributor.