fix(sdmx_series_ecb_gst): refresh content digest after key strip

sdmx_series_ecb_gst/meta.json

@@ -45,8 +45,8 @@
   "build": {
     "built_at": "2026-06-18T22:31:10.959751Z",
     "parsimony_version": null,
-    "builder": null,
-    "content_sha256": "1c86db0ca83453efff575b9c5201f4542e922d497a3c4186111c677b9e3a1158",
+    "builder": "strip-ecb-flow-prefix-keys",
+    "content_sha256": "c9e69ff15c7a191edf6699ade0819df8144a451f24cbde9f12ac8c441279bc20",
     "manifest_contract_sha256": "59b0110aeb53c89a979aacef8a36cd68de39d5819ec9efc6b32c8405b1b6fcb4"
   }
 }