Fires as a specific plugin is being deactivated.
This hook is the "deactivation" hook used internally by register_deactivation_hook(). The dynamic portion of the hook name,
$plugin, refers to the plugin basename.
If a plugin is silently deactivated (such as during an update), this hook does not fire.
(bool) Whether the plugin is deactivated for all sites in the network or just the current site. Multisite only. Default false.