Fix a bunch of compiler warnings (#10518)

Content.Server/Administration/Systems/AdminVerbSystem.Antags.cs

@@ -11,7 +11,6 @@ namespace Content.Server.Administration.Systems;
 
 public sealed partial class AdminVerbSystem
 {
-    [Dependency] private readonly IConfigurationManager _cfg = default!;
     [Dependency] private readonly ZombifyOnDeathSystem _zombify = default!;
     [Dependency] private readonly TraitorRuleSystem _traitorRule = default!;
     [Dependency] private readonly NukeopsRuleSystem _nukeopsRule = default!;