FIX: Docking mixin was not cleaning up timers (PR #12638)

I noticed this while trying to debug slow performing ember tests. Our docking mixin sometimes sets timers but never cancels them when removed. I’m not sure of any errors this causes but we should be tidying up whenever the component is removed.


Those are timers, not events.

Argh, you’re right. Updated.


oh my god I have no idea what’s wrong with me.