fix(sdmx_series_ecb_rpp): refresh content digest after key strip

sdmx_series_ecb_rpp/meta.json

@@ -42,8 +42,8 @@
   "build": {
     "built_at": "2026-06-18T22:34:46.970409Z",
     "parsimony_version": null,
-    "builder": null,
-    "content_sha256": "e30cad6a558e1c2c36274f19010c0902b6bebe8cb31d23d5b2147540f9a6858a",
+    "builder": "strip-ecb-flow-prefix-keys",
+    "content_sha256": "1ff10a38956f48b98fe234d75984ac1f0bc636b032c37fca22ac2dbce058d12e",
     "manifest_contract_sha256": "c31eb838dbd73f930bcfac8c9e7ba0c8fbf4e30a3cd081e8404dcaf9189a9d0c"
   }
 }