fix(sdmx_series_ecb_cbd2): refresh content digest after key strip

sdmx_series_ecb_cbd2/meta.json

@@ -69,8 +69,8 @@
   "build": {
     "built_at": "2026-06-18T22:29:56.302885Z",
     "parsimony_version": null,
-    "builder": null,
-    "content_sha256": "2ed7ba1950d63cd4bbe5f07893793f3b39d7c9399b00b7d1114a29bc01b658ca",
+    "builder": "strip-ecb-flow-prefix-keys",
+    "content_sha256": "a83c92195596775477c66fad800ddeeb76c7733ae13614b8965e405c27723d44",
     "manifest_contract_sha256": "d5ecbf61174552bc9a85f2e81c09c13f2ff8c3deeb42e40934a2a6c2dd21cd2e"
   }
 }