fix: trait impl in test

Author: hstove

stackslib/src/chainstate/coordinator/tests.rs

@@ -446,6 +446,7 @@ impl BlockEventDispatcher for NullEventDispatcher {
         _burns: u64,
         _slot_holders: Vec<PoxAddress>,
         _consensus_hash: &ConsensusHash,
+        _parent_burn_block_hash: &BurnchainHeaderHash,
     ) {
     }
 }