remove enterprise search from default distribution (#16818)

Elastic App Search and Elastic Workplace Search are deprecated and removed from v9
- remove enterprise_search integration plugin from default plugins
- add breaking change doc

Co-authored-by: Karen Metts <[email protected]>

docs/static/breaking-changes-90.asciidoc

@@ -223,3 +223,14 @@ removed and their replacements.
 |=======================================================================
 
 ====
+
+[discrete]
+[[enterprise_search-deprecated-9.0]]
+===== App Search and Workplace Search plugins are deprecated
+
+Enterprise Search is deprecated and no longer supported from {stack} 9.0. 
+We've also deprecated the {ls} App Search and Workplace Search plugins. 
+These plugins will receive only security updates and critical fixes moving forward. 
+
+We recommend using our native {es} tools for your Search use cases.
+For more details, please visit https://www.elastic.co/guide/en/search-ui/current/tutorials-elasticsearch.html[Search UI with Elasticsearch].

rakelib/plugins-metadata.json

@@ -410,8 +410,8 @@
     "skip-list": false
   },
   "logstash-integration-elastic_enterprise_search": {
-    "default-plugins": true,
-    "skip-list": false
+    "default-plugins": false,
+    "skip-list": true
   },
   "logstash-input-elastic_serverless_forwarder": {
     "default-plugins": true,