Statusbar only updates on /otr action, not window switch

[robchahin]

The 'otr' statusbar item becomes much less useful when it doesn't update itself when switching between query windows, else you end up switching from an OTR query to a cleartext query, but the statusbar still says OTR.

Manually running /otr when switching to a query works, but seems unnecessary. The UX would be much better if the statusbar redraw was triggered whenever switching to a new query window.