3939 [image_picker] Fix camera alert localization analyzer warning (cla: yes, p: image_picker, platform-ios)

3956 [image_picker] Change storage location for camera captures to internal cache on Android, to comply with new Google Play storage requirements.  (cla: yes, waiting for tree to go green, p: image_picker, platform-android)

3960 Use collection and box literals in ObjC code (cla: yes, p: webview_flutter, p: camera, p: google_maps_flutter, p: image_picker, p: in_app_purchase, platform-ios)