[3.13] gh-121018: Fix more cases of exiting in argparse when exit_on_error=False (GH-121056)

[serhiy-storchaka]

• parse_intermixed_args() now raises ArgumentError instead of calling error() if exit_on_error is false.
• Internal code now always raises ArgumentError instead of calling error(). It is then caught at the higher level and error() is called if exit_on_error is true. (cherry picked from commit 81a654a)

• Issue: argparse.ArgumentParser.parses_args does not honor exit_on_error=False when given unrecognized arguments #121018