Replace Rollup with Downsampling in changelog schema (#96942)

Author: salvatore-campagna

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

@@ -35,6 +35,7 @@
             "DLM",
             "Discovery-Plugins",
             "Distributed",
+            "Downsampling",
             "EQL",
             "Engine",
             "FIPS",
@@ -73,7 +74,6 @@
             "Ranking",
             "Recovery",
             "Reindex",
-            "Rollup",
             "SQL",
             "Search",
             "Security",