Unsubscribes to the specified workshop addon. Call steamworks.ApplyAddons afterwards to update.
This function should never
be called without a user's consent and should not be called if the addon is currently in use (aka: the user is not in the main menu) as it may result in unexpected behaviour.
Unsubscribes from the Gm_construct_Beta Steam Workshop addon, if subscribed, and reloads addons afterwards