fix(cli): handle new error message for malformed timestamp

Update test to accept both "Malformed timestamp" (introduced in cardano-cli
>= 10.14.0.0) and the previous "parseTimeOrError" error message. This
ensures compatibility with newer versions of cardano-cli.

Author: mkoura

cardano_node_tests/tests/test_cli.py

@@ -1515,7 +1515,10 @@ def test_slot_number_invalid_format(
             cluster.g_query.query_cli(["slot-number", timestamp_str])
         exc_value = str(excinfo.value)
         with common.allow_unstable_error_messages():
-            assert "parseTimeOrError" in exc_value, exc_value
+            assert (
+                "Malformed timestamp" in exc_value  # In cardano-cli >= 10.14.0.0
+                or "parseTimeOrError" in exc_value
+            ), exc_value
 
     @allure.link(helpers.get_vcs_link())
     @pytest.mark.parametrize("time_val", ("above", "bellow"))