WooCommerce Memberships 1.26.11

* Fix - Errors with "Membership Note" email when using the experimental "Email Improvements" feature
* Dev - Add a filter hook on an existing membership found for a purchased plan

* Fix - Prevent members from being un-enrolled from courses when a membership transitions out of trial state
* Tweak - Performance improvements with `wc_memberships_get_memberships_from_subscription()` function

* Fix - Sensei `is_user_enrolled_in_course()` method not working as expected
* Fix - In some edge cases, product variations were restricted from purchase when they shouldn't have been
* Fix - Ensure subscription-linked memberships do not unexpectedly expire when the customer resubscribes
* Fix - When configuring a membership plan to auto-enroll in a course, users are now auto un-enrolled if/when their membership becomes inactive
* Fix - Remove deprecated usages of WooCommerce enhanced navigation feature