Doc: Troubleshoot missing graphics in monitoring topics

[karenzone]

Topics

• Collect Logstash monitoring data for dashboards
• Collect Logstash monitoring data for stack monitoring

These topics aren't displaying screenshots properly.
To Do: Find out why and remedy.

Images not displaying

• image::../monitoring/images/integration-agent-add.png[Add agent flyout in {kib}]
• image::../monitoring/images/integration-agent-confirm.png[Agent confirm data]

Note to self @karenzone: Remove + in "Monitor Logstash logs and metrics" section of Collect Logstash monitoring data for stack monitoring topic.

[karenzone]

Note to self @karenzone: The troublemakers appear inside tabbed widgets. Look into that as a possible cause.

[karenzone]

Files are present, checked in with #15528

[karenzone]

Update: March 12, Tu.

The files are in the logstash repo, but not in built-docs. Not sure why that's the case, but it explains the weird difference in behavior between the preview and the built docs.