Fix some build warnings (#2226)

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>

Content.Client/GameObjects/Components/Suspicion/SuspicionRoleComponent.cs

@@ -23,10 +23,7 @@ namespace Content.Client.GameObjects.Components.Suspicion
         [Dependency] private readonly IGameHud _gameHud = default!;
         [Dependency] private readonly IEntityManager _entityManager = default!;
         [Dependency] private readonly IOverlayManager _overlayManager = default!;
-        [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
         [Dependency] private readonly IResourceCache _resourceCache = default!;
-        [Dependency] private readonly IComponentManager _componentManager = default!;
-        [Dependency] private readonly IInputManager _inputManager = default!;
         [Dependency] private readonly IEyeManager _eyeManager = default!;
 
         private SuspicionGui? _gui;

Content.Client/GameObjects/EntitySystems/AtmosDebugOverlaySystem.cs

@@ -22,7 +22,6 @@ namespace Content.Client.GameObjects.EntitySystems
     internal sealed class AtmosDebugOverlaySystem : SharedAtmosDebugOverlaySystem
     {
         [Dependency] private readonly IMapManager _mapManager = default!;
-        [Dependency] private readonly IResourceCache _resourceCache = default!;
 
         private Dictionary<GridId, AtmosDebugOverlayMessage> _tileData =
             new Dictionary<GridId, AtmosDebugOverlayMessage>();

Content.Client/UserInterface/ItemSlotManager.cs

@@ -78,7 +78,10 @@ namespace Content.Client.UserInterface
                     grid.MapToGrid(mousePosWorld), args.PointerLocation, item.Uid);
 
                 // client side command handlers will always be sent the local player session.
-                var session = _playerManager.LocalPlayer.Session;
+                var session = _playerManager.LocalPlayer?.Session;
+                if (session == null)
+                    return false;
+                
                 inputSys.HandleInputCommand(session, func, message);
             }
             else