Addon icons get added/reordered in the toolbar

In legacy/trac#13318 (moved), we tried to set a specific ordering of our addons by setting browser.uiCustomization.state. Unfortunately, because our addons get installed at browser first run, this pref is getting altered and addons are installing themselves into the toolbar anyway, and in an order we do not control. This causes the browser.uiCustomization.state pref to get reset.

Ideally, we'd be able to enforce this pref's original values upon addons after their installation. Unfortunately, resetting this pref to its original default value does not take effect until after browser restart. We need to somehow tell the browser to reorganize the addons back to this default state after their installation.