Fork TransportClusterHealthAction to MANAGEMENT (#96546)

This action can become fairly expensive for large states. Plus it is
called at high rates on e.g. Cloud which is blocking transport threads
needlessly in large deployments. Lets fork it to MANAGEMENT like we do
for similar CPU bound actions.

Backport of #90621 to 7.17

Co-authored-by: Armin Braun <me@obrown.io>

server/src/main/java/org/elasticsearch/action/admin/cluster/health/TransportClusterHealthAction.java

@@ -66,7 +66,7 @@ public TransportClusterHealthAction(
             ClusterHealthRequest::new,
             indexNameExpressionResolver,
             ClusterHealthResponse::new,
-            ThreadPool.Names.SAME
+            ThreadPool.Names.MANAGEMENT // fork to management since the health computation can become expensive for large cluster states
         );
         this.allocationService = allocationService;
     }