Remove getUnloadingChunkHolder check

It always returns null now. So it could NPE and is not useful.

patches/server/Fix-CraftWorld-isChunkGenerated.patch

@@ -24,9 +24,6 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +            }, world.getChunkSource().mainThreadProcessor).join();
 +        }
 +        ChunkAccess chunk = world.getChunkSource().getChunkAtImmediately(x, z);
-+        if (chunk == null) {
-+            chunk = world.getChunkSource().chunkMap.getUnloadingChunkHolder(x, z).getLatestChunk();
-+        }
 +        if (chunk != null) {
 +            return chunk instanceof ImposterProtoChunk || chunk instanceof net.minecraft.world.level.chunk.LevelChunk;
          }