Flutter 3.5.0

• Removed call to Purchases.getSharedInstance().close(); in onDetachedFromEngine. This should fix an incompatibility with workmanager Flutter plugin that was causing the BillingClient to get disconnected after a task would finish.
• Added a new close() function to be called in Android whenever the resources used by Purchases should be released.
  https://github.com/RevenueCat/purchases-flutter/pull/268
  https://github.com/RevenueCat/purchases-flutter/issues/257
• Bumppurchases-hybrid-common to 1.9.3 Changelog here
• Bump purchases-ios to 3.12.8
  3.12.8 Changelog here
  3.12.7 Changelog here

To view new release, visit https://github.com/RevenueCat/purchases-flutter/releases/tag/3.5.0