From the REPL, on a Fun House.

import supervisor
supervisor.set_rgb_status_brightness(0)

Causes a reboot of the board.
On latest it reboots into Hard Crash safe mode, on 7.1.1 it just resets.

I tested it on QTPY ESP32, Clue, Gemma (because of the dotstar), FeatherS2 (ESP and dotstar) and could not reproduce.