* Flip the component pref to true by default for nightly builds only
* Move the pref check and initialization to a startup idle task
* And be a bit smarter about when we get and disable the addon
* Fix a bug where we try to communicate with the overlay after the window actor is destroyed when
the component pref gets flipped off during use
Differential Revision: https://phabricator.services.mozilla.com/D196888