Use a noop reducer

[zalmoxisus]

I see the reducer is handling TOGGLE_VISIBILITY, but it is not dispatched from anywhere. Is it an orphaned code that should be removed?

[romseguy]

Legacy code yes, redux-devtools wasn't implementing visibility state as far as I remember. I don't think we care too much about bundle size since it's a dev tool, so maybe we should just use a noop here instead of removing the reducer and actions files, could make potential future improvements more straightforward... We have git history of course but the convenience here looks free from drawbacks to me.

[zalmoxisus]

Of course, if we'll use a noop function and those files won't be imported, it wouldn't affect the bundle size as well. I am working on adding support for monitors reducers into Redux DevTools Extension, and was wondering about extra operations.