Initializing UI features, like keyboard shortcuts, by chaining
onto APP.conference.init is not safe because init can fail,
skipping the initializing of UI features. This can happen when
the room is locked and then a failure event is dispatched into
middleware. I couldn't find a place to properly chain onto
in the APP.conference.init promise chain, primarily due
to the flow continued within middleware, so instead I
leveraged an existing listener for CONFERENCE_JOINED.
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