fix(transaction): handle fee parsing for newer CLI output

Updated the fee parsing logic to handle the new CLI output format where
the fee is followed by "Lovelace". This ensures compatibility with both
the new and old versions of the `build` command.

Author: mkoura

cardano_clusterlib/transaction_group.py

@@ -1013,13 +1013,15 @@ def build_tx(  # noqa: C901
             *self._clusterlib_obj.magic_args,
             *self._clusterlib_obj.socket_args,
         ]
-        stdout = self._clusterlib_obj.cli(cli_args).stdout
+        stdout = self._clusterlib_obj.cli(cli_args).stdout.strip()
         stdout_dec = stdout.decode("utf-8") if stdout else ""
 
-        # check for the presence of fee information so compatibility with older versions
-        # of the `build` command is preserved
+        # Check for the presence of fee information. No fee information was provided in older
+        # versions of the `build` command.
         estimated_fee = -1
-        if "transaction fee" in stdout_dec:
+        if stdout_dec.endswith("Lovelace"):
+            estimated_fee = int(stdout_dec.split()[-2])
+        elif "transaction fee" in stdout_dec:
             estimated_fee = int(stdout_dec.split()[-1])
 
         return structs.TxRawOutput(