flatten_references_graph: remove unused fixture and all real /nix/store paths from tests

pkgs/by-name/fl/flattenReferencesGraph/src/flatten_references_graph/__test_fixtures/flatten-references-graph-main-input-no-paths.json

@@ -4,7 +4,7 @@
       "closureSize": 168,
       "narHash": "sha256:0dl4kfhb493yz8a5wgh0d2z3kr61z65gp85vx33rqwa1m1lnymy8",
       "narSize": 168,
-      "path": "/nix/store/1kaw7p40kknss1qq8gark3azvfp26q8x-no-store-paths-base.json",
+      "path": "/nix/store/fakehash000000000000000000000000-no-store-paths-base.json",
       "references": []
     }
   ],
@@ -18,6 +18,6 @@
     ]
   ],
   "exclude_paths": [
-    "/nix/store/1kaw7p40kknss1qq8gark3azvfp26q8x-no-store-paths-base.json"
+    "/nix/store/fakehash000000000000000000000000-no-store-paths-base.json"
   ]
 }