fix(sdmx_series_ecb_esb): strip flow-id prefix from series keys

sdmx_series_ecb_esb/meta.json

@@ -51,8 +51,8 @@
   "build": {
     "built_at": "2026-06-18T22:30:41.965778Z",
     "parsimony_version": null,
-    "builder": null,
-    "content_sha256": "cab4b96eae147b3bfc488fc65a208796b2e05a9bc27fe78b1c1b22ba0c0b6e42",
+    "builder": "strip-ecb-flow-prefix-keys",
+    "content_sha256": "3af1211556f074d9d43f049cb5f6f8f1b621735b6ac60bf95a3fa1713622fc7e",
     "manifest_contract_sha256": "26788f45a56247c01077d72093d439ba3eb54d67aeedff64f18b1c5477da6860"
   }
 }

sdmx_series_ecb_esb/series.parquet

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:3e52c4c5c0be0900ce96760cfcfba3d8bc446736007994ce32ec5214b04116af
-size 41040
+oid sha256:3c27017d42740ad13102ad9445c1e21f18b0ac08aa0db38b5878630a071baa42
+size 59638