Fix small overread during SASLprep

When Who What
2024-09-18 14:53:01 Nathan Bossart (bossartn) Closed in commitfest 2024-11 with status: Committed
2024-09-18 14:53:01 Nathan Bossart (bossartn) Changed committer to d_gustafsson
2024-09-09 15:30:37 Jacob Champion (jchampion) Changed authors to Jacob Champion (jchampion)
2024-09-09 15:30:37 Jacob Champion (jchampion) Changed targetversion to stable
2024-09-09 15:30:28 Jacob Champion (jchampion) Attached mail thread CAOYmi+mTnmM172g=_+Yvc47hzzeAsYPy2C4UBY3HK9p-AXNV0g@mail.gmail.com
2024-09-09 15:30:28 Jacob Champion (jchampion) Created patch record