Update build tools changelog schema for new Core/Infra/Metrics label (#105016) (#105032)

a new Core/Infra/Metrics label has been added, this commit updates the schema

Author: pgomulka

build-tools-internal/src/main/resources/changelog-schema.json

@@ -55,6 +55,7 @@
             "Infra/Scripting",
             "Infra/Settings",
             "Infra/Transport API",
+            "Infra/Metrics",
             "Ingest",
             "Ingest Node",
             "Java High Level REST Client",