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.IntegrationTests/ContentIntegrationTest.cs

@@ -13,7 +13,7 @@ namespace Content.IntegrationTests
         {
             options = options ?? new ClientIntegrationOptions();
             // ReSharper disable once RedundantNameQualifier
-            options.ClientContentAssembly = typeof(Client.EntryPoint).Assembly;
+            options.ClientContentAssembly = typeof(EntryPoint).Assembly;
             options.SharedContentAssembly = typeof(Shared.EntryPoint).Assembly;
             options.BeforeStart += () =>
             {