Update to "read_pipeline" permission (#26465)

I don't know in what version this was updated to be called "read_pipeline". but it is available through the roles settings in Kibana.

libbeat/docs/security/users.asciidoc

@@ -279,7 +279,7 @@ endif::no_ilm[]
 
 ifeval::["{beatname_lc}"=="filebeat"]
 |Cluster
-|`cluster:admin/ingest/pipeline/get`
+|`read_pipeline`
 |Check for ingest pipelines used by modules. Needed when using modules.
 endif::[]