Re-implement parallel for pathfinding crumbs (#12355)

Content.Server/NPC/Pathfinding/PathfindingSystem.cs

@@ -15,6 +15,7 @@ using Robust.Shared.Physics.Components;
 using Robust.Shared.Physics.Systems;
 using Robust.Shared.Players;
 using Robust.Shared.Random;
+using Robust.Shared.Threading;
 using Robust.Shared.Timing;
 using Robust.Shared.Utility;
 
@@ -37,6 +38,7 @@ namespace Content.Server.NPC.Pathfinding
 
         [Dependency] private readonly IAdminManager _adminManager = default!;
         [Dependency] private readonly IGameTiming _timing = default!;
+        [Dependency] private readonly IParallelManager _parallel = default!;
         [Dependency] private readonly IPlayerManager _playerManager = default!;
         [Dependency] private readonly IRobustRandom _random = default!;
         [Dependency] private readonly DestructibleSystem _destructible = default!;