libtmux(test[logging]): remove caplog.text string matching per CLAUDE.md

why: CLAUDE.md logging standards require asserting on caplog.records
attributes, not string matching on caplog.text. The rec.exc_info is None
assertion already covers the guarantee.
what:
- Remove redundant `assert "Traceback" not in caplog.text` from
  test_options_warning_no_exc_info

Author: tony

tests/test_logging.py

@@ -315,4 +315,3 @@ def test_options_warning_logging_schema(
     rec = t.cast(t.Any, records[0])
     assert isinstance(rec.tmux_option_key, str)
     assert rec.exc_info is None
-    assert "Traceback" not in caplog.text