RADIUS authentication can be handled by a variety of mechanisms,
including proxy for 2FA systems requiring user interaction with a
separate device, token acquisition, or other time-consuming action.

Given the delays required for certain 2FA implementations, a thirty
second timeout can range from onerous to untenable. Accomodate the
2FA time requirements by extending the hard-coded RADIUS time limit
from 30 seconds to 240.

This is https://github.com/vyos/vyos-1x/pull/1236 on GH