3870 [in_app_purchase] iOS example using in_app_purchase_ios package (cla: yes, p: in_app_purchase, platform-ios)

3871 Update instructions on running integration_test with the flutter driver (cla: yes)

3872 Exclude some missing integration tests (cla: yes)

3873 [image_picker] Image picker fix metadata (cla: yes, p: image_picker, platform-ios)

3874 [in_app_purchase] Expose in_app_purchase_exception.dart correctly (cla: yes, p: in_app_purchase, platform-ios)

3875 Temporarily run Windows tests via GitHub Actions (cla: yes)

3876 [google_sign_in] document web usage (cla: yes, p: google_sign_in)