Cleanup warnings: CS8321, CS0105, CS0168 (#36949)

* Clean up

* CS0168

Content.Server/Entry/EntryPoint.cs

@@ -221,6 +221,7 @@ namespace Content.Server.Entry
             Load(CCVars.ConfigPresetDebug, "debug");
 #endif
 
+#pragma warning disable CS8321
             void Load(CVarDef<bool> cVar, string name)
             {
                 var path = $"{ConfigPresetsDirBuild}{name}.toml";
@@ -230,6 +231,7 @@ namespace Content.Server.Entry
                     sawmill.Info("Loaded config preset: {Preset}", path);
                 }
             }
+#pragma warning restore CS8321
         }
     }
 }

Content.Server/Explosion/EntitySystems/ExplosionSystem.Processing.cs

@@ -146,7 +146,7 @@ public sealed partial class ExplosionSystem
             }
 #if EXCEPTION_TOLERANCE
             }
-            catch (Exception e)
+            catch (Exception)
             {
                 // Ensure the system does not get stuck in an error-loop.
                 if (_activeExplosion != null)

Content.Server/Polymorph/Systems/PolymorphSystem.cs

@@ -2,7 +2,6 @@ using Content.Server.Actions;
 using Content.Server.Humanoid;
 using Content.Server.Inventory;
 using Content.Server.Mind.Commands;
-using Content.Shared.Nutrition;
 using Content.Server.Polymorph.Components;
 using Content.Shared._DV.Polymorph; // DeltaV
 using Content.Shared.Actions;