WooCommerce Subscriptions 6.9.0

* Tweak: Update WooCommerce tested up to compatibility flag.
* Fix: [GDPR] While processing erasure requests anonymise all user subscriptions with any status. PR#2720
* Fix: Fix PHP warnings which appear on the WooCommerce > Settings > Accounts & Privacy page and while exporting user personal data. PR#2719

* New: [GDPR] Export and erase subscription personal data when processing user export and erasure requests. PR#2692
* New: [GDPR] Add an automatic data removal system for ended subscriptions and their related orders. PR#2702
* New: [GDPR] Add details about the personal data the plugin collects to the privacy policy guide. PR#2700
* Tweak: Reorder wcs_get_subscriptions_for_order logic to be more performance friendly. PR#2697
* Tweak: Replace remote image sources with an internal asset. PR#2690
* Fix: [WC3.4] Prevent subscription related orders from being trashed/anonymised by WC's automatic clean up system. PR#2698
* Fix: [WC3.4] Only trigger the woocommerce_before_add_to_cart_button action hook once on variable subscription single product pages. PR#2706

* Fix: With Mixed Checkout disabled, only remove the add to cart notice when redirected straight to checkout. Fixes issue where error notices are removed incorrectly. PR#2541
* Fix: With Mixed Checkout disabled, only empty cart when the variation ID is the same but with different attributes. PR#2540
* Fix: Remove the "\n" character from variable subscription item tooltips in the admin subscriptions table. PR#2481
* Fix: Allow users to purchase limited to any status subscription products under circumstances where the customer is blocked from purchasing because of cancelled orders. PR#2485
* Fix: Prevent deletion of product variations in use by a subscription. PR#2507
* Fix: Get default product price when no price arg is passed into `get_price_string()`. PR#2558
* Fix: Avoid potential for division by zero errors when switching. PR#2574
* Fix: Only force payment method selection during switch if a new subscription will be created. PR#2567
* Fix: Remove trailing space from address_type variable. PR#2595
* Fix: Ensure the opening span tag is present for all args passed to get_price_string(). PR#2597
* Fix: Set the product's price to the sale price even if it's 0. Fixes display issues with subscription products on sale for $0. PR#2601
* Fix: While resubscribing, ensure subscriptions with multiple line items charge the correct amount for all line items, not just the 1st. PR#2585
* Fix: Hide product stock settings while editing variable products. PR#2563
* Fix: Allow subscription coupons to be applied while switching subscriptions. PR#1863
* Fix: Ensure subscriptions created via the API with an active status and a set_paid arg set to true are saved. PR#2609
* Fix: Ensure Net Gain/Loss calculations for subscription reports convert dates correctly to match the site's timezone. PR#2593
* Fix: Prevent the possibility for fatal errors caused by calling undeclared functions during the payment method change requests. PR#2613
* Tweak: Ensure sign up fees are numeric before attempting to use them in calculations. PR#2551
* Tweak: Only clear related order cache on renewal order changes. PR#2555
* Tweak: Improve checkout performance by avoiding related renewal orders query. PR#2550
* Tweak: Add the `$plain_text` arg to order item meta start and end hooks. PR#2515
* Tweak: Refactor the view subscription template. PR#2575
* Tweak: Add Subscription My Account endpoints to wpml-config.xml file. PR#2578
* Tweak: Add 'woocommerce_subscriptions_product_limited_for_user' filter. PR#2596
* Tweak: Clear the cart if the product being added to the cart is sold individually when mixed checkout is disabled. PR#2602
* Tweak: Use WC_DateTime objects and `getTimestamp()` rather than `format( 'U' )` to avoid possible issues in earlier PHP versions. PR#2588
* Tweak: Add pagination to the My Account Subscriptions table. PR#2537
* Tweak: Catch, log and display an admin notice after a scheduled subscription action timeout. PR#2484