update custom dashboard docs (#6470)

Author: angorayc

docs/dashboards/dashboards-overview.asciidoc

@@ -17,8 +17,6 @@ To create a new custom dashboard, click **Create Dashboard**. You can control wh
 
 To create a new tag or edit existing tags, open the **Tags** menu and click **Manage tags**.
 
-TIP: To make a custom dashboard appear on this page, assign it the tag **Security Solution**.
-
 image::images/dashboards-landing-page.png[The dashboards landing page, 75%]
 
 Refer to documentation for the other {elastic-sec} dashboards to learn more about them. For more information about creating custom dashboards, refer to {kibana-ref}/create-a-dashboard-of-panels-with-web-server-data.html[Create your first Kibana dashboard].