[7.9] [DOCS] Adds missing monitoring.cluster_alerts.email_notifications.email_address monitoring setting (elastic#126826) (elastic#127358)

* [DOCS] Adds missing `monitoring.cluster_alerts.email_notifications.email_address` monitoring setting (elastic#126826)

* [DOCS] Adds missing deprecated monitoring settings

* Review comments

Co-authored-by: Kibana Machine <[email protected]>
(cherry picked from commit 0bc7a2e)

* Removes deprecation message

Co-authored-by: Kibana Machine <[email protected]>

Author: KOTungseth

docs/settings/monitoring-settings.asciidoc

@@ -31,6 +31,9 @@ For more information, see
 
 [cols="2*<"]
 |===
+| `monitoring.cluster_alerts.email_notifications.email_address` {ess-icon}::
+  | When enabled, specifies the email address where you want to receive cluster alert notifications.
+
 | `monitoring.enabled`
   | Set to `true` (default) to enable the {monitor-features} in {kib}. Unlike the
   <<monitoring-ui-enabled, `monitoring.ui.enabled`>> setting, when this setting is `false`, the