Rework ember hook

Ref #65 as possibly resolved. Thanks Night for the reproduction of this.

STR the bug this fixed:
Open channel, wait for chat to load.
Inject script lazily (put whole script in console)
Emote menu button shows up
Click the "Games" directory on the left
Click a game, then a channel

Expected: emote menu shows
Actual: emote menu does not re-inject