* Don't show camera options for a file upload that would result in nothing happening for the user.

On Android, if the application declares the camera permission, then even intents
that use the camera require permission to be granted. This is a problem for apps
that combine an in-app camera with a WebView that has file uploading and the user
has not given permission for the camera.

Note, this will not request permission for camera. This will simply prevent
showing the camera options that would be a no-op action for users. It does this
by checking if the camera permission is declared, and if so, checks that the
user has granted permission.

More information: https://blog.egorand.me/taking-photos-not-so-simply-how-i-got-bitten-by-action_image_capture/

* Add example and documentation about camera option availability in file uploads for Android.