fix uncaught `BdbQuit` exceptions on ipdb `exit` - `BdbQuit` is now handled in the top-most scope of `InteractiveShell.run_code`. This ensures that `BdbQuit` is correctly handled but can still do its job of breaking out of all user code/loops/further breakpoint requests. Hopefully will work better than previous attempts, which put the `BdqQuit` handling in `Pdb.set_trace` - fixes: - jupyterlab/jupyterlab#12501 - refs: - ipython/ipython#876 - ipython/ipython#1273 - ipython/ipython#4474 - ipython/ipython#5306 - ipython/ipython#9731 - ipython/ipython#9942 - ipython/ipython#9950 - ipython/ipython#10006 - ipython/ipython#12378