CQ: Refactor Recurring Contribution Forms
The contributionrecur forms have poor test coverage, are inconsistent with each other and do not have sensible parameters being passed to them (eg. recur_id). This is a meta issue to track improvements to these forms: CRM/Contribute/Form/CancelSubscription CRM/Contribute/Form/UpdateBilling CRM/Contribute/Form/UpdateSubscription
All 3 forms have been converted to inherit from the parent class
CRM/Contribute/Form/ContributionRecur and common functionality will gradually be moved there.