Core/Instances: Sprinkle some thread safety on InstanceLockMgr

Port From (https://github.com/TrinityCore/TrinityCore/commit/0be72f68c33617d78a4139f3e667b03d0a22a435)

Source/Game/Maps/Instances/InstanceLockManager.cs

@@ -36,6 +36,7 @@ namespace Game.Maps
 
     public class InstanceLockManager : Singleton<InstanceLockManager>
     {
+        object _lockObject = new();
         Dictionary<ObjectGuid, Dictionary<InstanceLockKey, InstanceLock>> _temporaryInstanceLocksByPlayer = new(); // locks stored here before any boss gets killed
         Dictionary<ObjectGuid, Dictionary<InstanceLockKey, InstanceLock>> _instanceLocksByPlayer = new();
         Dictionary<uint, SharedInstanceLockData> _instanceLockDataById = new();
@@ -150,6 +151,7 @@ namespace Game.Maps
 
         public InstanceLock FindActiveInstanceLock(ObjectGuid playerGuid, MapDb2Entries entries)
         {
+            lock(_lockObject)
                 return FindActiveInstanceLock(playerGuid, entries, false, true);
         }
 
@@ -199,6 +201,8 @@ namespace Game.Maps
         {
             InstanceLock instanceLock = FindActiveInstanceLock(playerGuid, entries, true, true);
             if (instanceLock == null)
+            {
+                lock (_lockObject)
                 {
                     // Move lock from temporary storage if it exists there
                     // This is to avoid destroying expired locks before any boss is killed in a fresh lock
@@ -221,6 +225,7 @@ namespace Game.Maps
                         }
                     }
                 }
+            }
 
             if (instanceLock == null)
             {
@@ -237,7 +242,9 @@ namespace Game.Maps
                     instanceLock = new InstanceLock(entries.MapDifficulty.MapID, (Difficulty)entries.MapDifficulty.DifficultyID,
                         GetNextResetTime(entries), updateEvent.InstanceId);
 
+                lock(_lockObject)
                     _instanceLocksByPlayer[playerGuid][entries.GetKey()] = instanceLock;
+
                 Log.outDebug(LogFilter.Instance, $"[{entries.Map.Id}-{entries.Map.MapName[Global.WorldMgr.GetDefaultDbcLocale()]} | " +
                     $"{entries.MapDifficulty.DifficultyID}-{CliDB.DifficultyStorage.LookupByKey(entries.MapDifficulty.DifficultyID).Name}] Created new instance lock for {playerGuid} in instance {updateEvent.InstanceId}");
             }