strip leftover sdmx key from catalog meta.json

meta.json

@@ -25,6 +25,5 @@
     "builder": "packages/destatis/scripts/build_catalog.py",
     "content_sha256": "361cc548fb4d6e09875685f39e82351ba802e881ae528a87c5ae10b64f8b0580",
     "manifest_contract_sha256": "dfd8d06c4b9825b80f838168a33bc8f63ff123fd2126956cba2018bb705a6903"
-  },
-  "sdmx": null
-}
+  }
+}