fix(sdmx_series_ecb_ecs): refresh content digest after key strip

sdmx_series_ecb_ecs/meta.json

@@ -39,8 +39,8 @@
   "build": {
     "built_at": "2026-06-18T22:30:08.586049Z",
     "parsimony_version": null,
-    "builder": null,
-    "content_sha256": "55666617ca1868ef89545ad82a85fdb26db6eb5af3bc26045d7756b842cd6746",
+    "builder": "strip-ecb-flow-prefix-keys",
+    "content_sha256": "d41893df09da0b73b48ef10cea67078bb39f687688b423f245f0c6557203ba79",
     "manifest_contract_sha256": "77b5532569792a891c7a3dcf5b7e4169a859d5b43d965ac2e243932470adc266"
   }
 }