Add span tag while enabling or disbling apps as well.

I had made a PR : https://github.com/owncloud/core/pull/2853 which added a span element inside the a tag. This PR adds the same span element while the app is being enabled to prevent style errors. Please check : @Raydiation @tanghus @jancborchardt. 

Also, we need to backport this as the commits of my previous PR were also back-ported.

Thanks