Update test_all.py

Fix integration test

Author: cffls

integration-test/test/test_all.py

@@ -278,7 +278,8 @@ def test_plutus(self):
 
         non_nft_utxo = None
         for utxo in self.chain_context.utxos(str(taker_address)):
-            if isinstance(utxo.output.amount, int):
+            # multi_asset should be empty for collateral utxo
+            if not utxo.output.amount.multi_asset:
                 non_nft_utxo = utxo
                 break