Check if football notifications are available in Bridget `Notifications` service

[JamieB-gu]

On match info and liveblog pages we offer the ability to sign up for notifications about that match. However, the apps also allow users to sign up for notifications about a particular team, which will include the matches they're playing in. Therefore we don't want to offer the option to sign up for these matches separately, as this will result in duplicate notifications.

Currently the apps solve this problem by removing the button and instead displaying a message explaining that the user has already signed up for team notifications. We need a new Bridget API to check with the app whether this is the case, and adjust the webview UI accordingly.