fix issue resulting from kenny's apatch addiction

patches/server/Replace-player-chunk-loader-system.patch

@@ -1445,8 +1445,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 -                });
 +                // Paper - no-tick view distance - moved to Chunk neighbour update
              });
-         }, this.mainThreadExecutor); // Paper - queue to execute immediately so this doesn't delay chunk unloading
-         return completablefuture1;
+         }, (runnable) -> {
+             this.mainThreadMailbox.tell(ChunkTaskPriorityQueueSorter.message(holder, runnable));
 @@ -0,0 +0,0 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
              int k = this.viewDistance;