fix: assert full resolved config path in rate-limit output test

Agent-Logs-Url: https://github.com/github/spec-kit/sessions/86df9557-54f1-4fe4-a25f-9501cb2356cf

Co-authored-by: mnriem <15701806+mnriem@users.noreply.github.com>

Author: Copilot

tests/test_upgrade.py

@@ -279,7 +279,7 @@ def test_failure_prints_installed_plus_one_line_reason(
         assert "Installed: 0.7.4" in output
         if expected_reason == _RATE_LIMITED_REASON:
             assert "Could not check latest release: rate limited" in output
-            assert "auth.json" in output
+            assert str(_default_config_path()) in output
         else:
             assert f"Could not check latest release: {expected_reason}" in output