fix(sdmx_series_ecb_esa): refresh content digest after key strip

sdmx_series_ecb_esa/meta.json

@@ -51,8 +51,8 @@
   "build": {
     "built_at": "2026-06-18T22:30:35.785184Z",
     "parsimony_version": null,
-    "builder": null,
-    "content_sha256": "b88a9a3442a2bcb4f5057ba643545d0b36b788bc1f38cc066e56bfa5127f5770",
+    "builder": "strip-ecb-flow-prefix-keys",
+    "content_sha256": "4ca7ffee30c5d4579a6d19cae35eafc3baae196b277ae8f46f52988b21df7d7b",
     "manifest_contract_sha256": "60f450efb248c3dddbb0748b4f0068872cb60b21bd6bb285ef7446918136625c"
   }
 }