fix(sdmx_series_ecb_rtd): refresh content digest after key strip

sdmx_series_ecb_rtd/meta.json

@@ -36,8 +36,8 @@
   "build": {
     "built_at": "2026-06-18T22:34:55.798899Z",
     "parsimony_version": null,
-    "builder": null,
-    "content_sha256": "c2b1bdfab2524ebf33e2263fb3afda27775176bfa4a9901868bc41aa85484269",
+    "builder": "strip-ecb-flow-prefix-keys",
+    "content_sha256": "bd98d3e026a29c38704ad32e4c9a01e2521a4409184e86463902945b2c13439c",
     "manifest_contract_sha256": "0b159a7c33fa3c0ac07b4ea7f9668e8f46e920f6181520c19ac9abef7ea193fd"
   }
 }