Random events no longer start while in lobby and round ending forces current event to end (#1782)

* Random events cannot run in lobby and round ending forces events to end.

* Thanks p4merge

* Get rid of unused

* Apply suggestions from code review

Co-authored-by: Víctor Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>

Content.Server/StationEvents/StationEventCommand.cs

@@ -1,5 +1,4 @@
 #nullable enable
-using Content.Server.GameObjects.EntitySystems;
 using Content.Server.GameObjects.EntitySystems.StationEvents;
 using JetBrains.Annotations;
 using Robust.Server.Interfaces.Console;