python3Packages.llama-index-graph-stores-neo4j: fix build by setting hatchling as build-system

pkgs/development/python-modules/llama-index-graph-stores-neo4j/default.nix

···
   fetchPypi,
   neo4j,
   llama-index-core,
-  poetry-core,
+  hatchling,
   pythonOlder,
 }:
 
···
     hash = "sha256-Iumsnln5iGMAoB3aY4haecm87jYXlEW4/2+uppW8m9c=";
   };
 
-  build-system = [ poetry-core ];
+  build-system = [ hatchling ];
 
   dependencies = [
     neo4j