[3.10] gh-80254: Disallow recursive usage of cursors in `sqlite3` converters (#92274) * [3.10] gh-80254: Disallow recursive usage of cursors in `sqlite3` converters (#29054) (cherry picked from commit f629dcfe835e349433e4c5099381d668e8fe69c8) Co-authored-by: Sergey Fedoseev <fedoseev.sergey@gmail.com> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> * Fix ref leak in pysqlite_cursor_iternext