contract/consensus: Use less_than_strict for proposal lottery proof.

src/contract/consensus/proof/consensus_proposal_v1.zk

@@ -148,7 +148,7 @@ circuit "ConsensusProposal_V1" {
 	constrain_instance(headstart);
 
 	# Play lottery
-	less_than_loose(y, shifted_target);
+	less_than_strict(y, shifted_target);
 
 	# At this point we've enforced all of our public inputs.
 }