Update CI build failure email address

Author: russcam

.ci/jobs/defaults.yml

@@ -72,7 +72,7 @@
           .ci/run-tests
     publishers:
       - email:
-          recipients: infra-root+[email protected]
+          recipients: build-lang-clients@elastic.co
       - junit:
           results: "test_results/*-junit.xml"
           allow-empty-results: true