gh-134170: Add colorization to unraisable exceptions (#134183)

Default implementation of sys.unraisablehook() now uses traceback._print_exception_bltin() to print exceptions with colorized text.

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Victor Stinner <vstinner@python.org>