When calculating number of active subscriber, include archived plans (because they can be associated with active subscriptions)

[chrisjsimpson]

Is your feature request related to a problem? Please describe.
When calculating number of active subscriber, include archived plans (because they can be associated with active subscriptions- just because a plan is archived and no longer for sales does not mean existing subscribers's subscriptions are inactive to that plan)

Describe the solution you'd like
add .execution_options(include_archived=True) to get_number_of_active_subscribers

Describe alternatives you've considered

Additional context

subscribie/subscribie/blueprints/admin/stats.py

Line 17 in 9afcd49

.filter(PlanRequirements.subscription == 1)