tests: fix wallet creation for container tests (#1256)

Author: roman-khimov

pytest_tests/tests/container/test_container.py

@@ -46,7 +46,7 @@ def _create_multi_account_wallet(self, accounts: list[neo3_account.Account], pre
         for account in accounts:
             wallet.account_add(account)
         with open(wallet_path, "w") as out:
-            json.dump(wallet.to_json(self.DEFAULT_PASSWORD), out)
+            json.dump(wallet.to_json(self.neofs_env.default_password), out)
         return wallet_path
 
     def _refill_gas(self, wallet_path: str, address: str, amount: str = "200.0"):