Feed Failure Dialog

We need to have a dialog that opens when the feed fails to load. This feed should inform the user that the feed failed to load and allow them to load a different feed. The most common occurrence for the feed failing to load is when a custom search is done and the user requests more than 30K events.

This dialog should be very similar to the feed warning dialog (but for now should not replace the feed warning dialog). In the future we may be able to say that our interface can handle 30K loaded onto the map and we could remove the feed warning dialog.

• allow user to modify the search
• load the default feed instead

This should be triggered by an effect that reacts to loadEventsFailure. AutoUpdate should not trigger while in this "failed" state.