On mobile, the search field at the top of the channel list doesn't filter the channel list

[colons]

Instead, it filters the videos list, which surprised me a great deal given that it is almost completely obscured. Video search should be at the top of the video view.

When you're subbed to several hundred channels, finding individual ones is pretty difficult when you're using the app as a home-screen PWA and you don't have a ctrl+f equivalent. I'd submit a PR that alphabetises the list, but I'm certain it'd conflict with #24.