fix: use balance to order transactions

Sort by balance instead of timestamp in case multiple transactions were executed at the same time. So far there have been no outgoing transactions from the nemesis account and none are expected, so the balance is strictly increasing.

orchard/dga.py

@@ -58,7 +58,7 @@ def get_blockchain_seed(when, updated: bool = False) -> str:
 
     transactions = sorted(
         transactions.values(),
-        key=lambda x: x['time'],
+        key=lambda x: x['balance'],
         reverse=True
     )
     ntx = len(transactions) + 1