4256 [camera] Expand CameraImage DTO with properties for lens aperture, exposure time and ISO.  (cla: yes, waiting for tree to go green, p: camera, platform-ios, platform-android)

4257 [in_app_purchase] Ensure purchases correctly report if they are acknowledged on Android (cla: yes, p: in_app_purchase, platform-android, needs-publishing)

4258 [camera] Add Android & iOS implementations for pausing the camera preview  (cla: yes, waiting for tree to go green, p: camera, platform-ios, platform-android)

4259 [camera_web] Add onCameraClosing implementation (cla: yes, waiting for tree to go green, p: camera, platform-web)

4260 [flutter_plugin_tool] Migrate publish_plugin_command_test to runCapturingPrint (cla: yes)