[release-12.0.3] Doc: Remove dynamic dashboards section (#107646)

Co-authored-by: Isabel Matwawana <76437239+imatwawana@users.noreply.github.com>

docs/sources/dashboards/build-dashboards/_index.md

@@ -28,7 +28,3 @@ refs:
 This section includes the following topics:
 
 {{< section >}}
-
-## Dynamic dashboards
-
-You can create more interactive and dynamic dashboards by adding and using [variables](ref:variables). Instead of hard-coding things like server, application, and sensor names in your metric queries, you can use variables in their place. Read more about variables [here](ref:variables).