[DOCS] Remove reference to field stats in security limitations
Original commit: elastic/x-pack-elasticsearch@9ca673ea36e6f76b419b0efb7d595a78695679cb
@@ -70,9 +70,7 @@ When a user's role enables document level security for an index:
Calling certain Elasticsearch APIs on an alias can potentially leak information
about indices that the user isn't authorized to access. For example, when you get
the mappings for an alias with the `_mapping` API, the response includes the
-index name and mappings for each index that the alias applies to. Similarly, the
-response to a `_field_stats` request includes the name of the underlying index,
-rather than the alias name.
+index name and mappings for each index that the alias applies to.
Until this limitation is addressed, avoid index and field names that contain
confidential or sensitive information.
