Add .refreshable to the ScheduleEmptyView

[Archichil]

Given:

Empty schedule (or schedule that ended) causes ScheduleEmptyView to show.

When:

In a few days API comes with a new schedule. User wants to update the schedule. He click on his group, but see ScheduleEmptyView which is normal behaviour, because previous schudule was cached to minimize loading time. User tries to update the schedule by pull-to-refresh, but he can't, because this view doesn't have .refreshable on it. And to force the refresh, he has to clear cache in settings (good if he knows it). I do not find it convenient.

Expected behaviour:

Be able to pull-to-refresh on ScheduleEmptyView