platform specific named pipe for windows

Author: mosche

x-pack/plugin/ml/src/main/plugin-metadata/entitlement-policy.yaml

@@ -7,3 +7,6 @@ org.elasticsearch.ml:
       - relative_path: "ml-local-data/"
         relative_to: data
         mode: read_write
+      - path: \\.\pipe\
+        mode: read_write
+        platform: windows