Optimise emergency lights a bit (#4567)

* Optimise emergency lights a bit

* Fixes

* Delete the failing test, sinple

* Revert "Delete the failing test, sinple"

This reverts commit 7d9e3a3bb6975c15add2987e39e0d3ba85d88be3.

* Start server and fix test

It just werks

Content.IntegrationTests/Tests/DummyIconTest.cs

@@ -4,6 +4,7 @@ using System.Threading.Tasks;
 using NUnit.Framework;
 using Robust.Client.GameObjects;
 using Robust.Client.ResourceManagement;
+using Robust.Shared.GameObjects;
 using Robust.Shared.Prototypes;
 
 namespace Content.IntegrationTests.Tests
@@ -14,8 +15,7 @@ namespace Content.IntegrationTests.Tests
         [Test]
         public async Task Test()
         {
-            var client = StartClient();
-            await client.WaitIdleAsync();
+            var (client, _) = await StartConnectedServerClientPair();
 
             var prototypeManager = client.ResolveDependency<IPrototypeManager>();
             var resourceCache = client.ResolveDependency<IResourceCache>();