Rider static analysis (#433)

* Non-accessed local variable

* Merge cast and type checks.

* StringComparison.Ordinal added for better culture support

* Supposed code improvement in launcher. Remove unused code.

* Update ExplosionHelper.cs

Unintentional change.

* Optimized Import

* Add Robust.Shared.Utility import where it was deleted

* Other random suggestion

* Improve my comment

Content.Server/GameObjects/Components/Mobs/FootstepSoundComponent.cs

@@ -1,12 +1,4 @@
 using Robust.Shared.GameObjects;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Content.Server.Mobs;
-using Robust.Shared.Interfaces.GameObjects;
-using Robust.Shared.ViewVariables;
 
 namespace Content.Server.GameObjects.Components.Mobs
 {