Issues Serializing Message int64 fields with 0 value

> MsgUnbondConvertAndStake.lockId:
https://github.com/osmosis-labs/osmosis/blob/feaa5ef7d01dc3d082b9d4e7d1dd846d2b54cf6d/proto/osmosis/superfluid/tx.proto#L247
> As experienced with the MsgUnlockAndMigrateSharesToFullRangeConcentratedPosition message (remember the struggle Adam), I'm running into signing issues when trying to pass a 0 value to an int64 representing the lockId. Somewhere in the pipeline it's getting omitted from the message and causing serialization/signing errors: perhaps it's being considered a null value?
> I think Matt Park we need to make the same changes we did for the migrate message above, and use a -1 value instead of 0 to signal a special case (here, the case of using liquid shares instead of locked shares)