[CoCo] "Break" key is picked up as a key when entering wifi password

[barbeque]

Pressing the break key while typing the wifi password in Config produces another diamond. It seems like the character is defined in cmoc as KEY_PROBE_BREAK = 0xFB.

It should either be filtered out of the input, or (ideally) bail you out of the process of entering the password and return to the "select a network" menu.