Fix SASL on libera.chat

[iglosiggio]

While deploying an IRC bot to libera.chat (w/@lartu) we were unable to connect via SASL because the ACK was never recognized.

The reason for that rested on a check that expected a weird leftover space character.

This PR checks that a trimmed version of the third argument is equal to sasl.

This is enough for our personal purposes but i'm not sure if it is a proper fix.

[ralyodio]

Pretty sure this project is dead. Its' been literally a year.