4514 Enable Android integration tests in remaining plugins (cla: yes, waiting for tree to go green, p: camera, p: in_app_purchase, p: url_launcher, p: video_player, p: shared_preferences, platform-android)

4517 [in_app_purchase] Fix CHANGELOG for 0.2.0. (cla: yes, waiting for tree to go green, p: in_app_purchase, platform-ios)

4518 [in_app_purchase] Rename iOS implementation to _storekit (cla: yes, p: in_app_purchase, platform-ios)

4523 [in_app_purchase] Emit empty list when no transactions to restore. (cla: yes, waiting for tree to go green, p: in_app_purchase)