ai: apply changes for #876 (1 review thread)

Addresses:
  - #3636506949 at src/databricks/sql/auth/oauth.py:246

Signed-off-by: peco-engineer-bot[bot] <peco-engineer-bot[bot]@users.noreply.github.com>

Author: peco-engineer-bot[bot]

src/databricks/sql/auth/oauth.py

@@ -247,6 +247,13 @@ def _on_timeout():
                 logger.error(msg)
                 raise RuntimeError(msg) from e
             except Exception as e:
+                # Record here too (like the OSError branch above) so the
+                # fall-through `raise last_error` always re-raises a real
+                # exception. If a non-OSError/non-webbrowser.Error is raised on
+                # every port, last_error would otherwise stay None and turn
+                # `raise last_error` into `raise None`, masking the real failure
+                # with a confusing TypeError.
+                last_error = e
                 logger.error("unexpected error: %s", e)
         if self.redirect_port is None:
             logger.error(