Fix content.integration tests warnings (#17817)

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

Content.IntegrationTests/Tests/Payload/ModularGrenadeTests.cs

@@ -1,7 +1,5 @@
-using System.Threading.Tasks;
 using Content.IntegrationTests.Tests.Interaction;
 using Content.Server.Explosion.Components;
-using NUnit.Framework;
 using Robust.Shared.Containers;
 using Robust.Shared.GameObjects;
 
@@ -73,4 +71,3 @@ public sealed class ModularGrenadeTests : InteractionTest
         AssertDeleted();
     }
 }
-