[Monitoring] Reactify icons in Pipeline Viewer

[elasticmachine]

Original comment by @justinkambic:

Presently the Logstash Pipeline Viewer is using icons that are defined in EUI. The PV does not use React and cannot easily reference the icons directly, so it instead references copies that live in Monitoring. We want to reference these icons directly from EUI if possible.

[elasticmachine]

Original comment by @justinkambic:

In LINK REDACTED we changed the references to import the SVGs directly from EUI. This is better, because we are directly referencing the assets in their own package, rather than copying them into the monitoring plugin. When we Reactify the Pipeline Viewer, we will want to transition these references to use the associated icon component.

[justinkambic]

@ycombinator do you think we still need to track this, given the current design goals of #18597?

[ycombinator]

@justinkambic I don't think so, given how far and well #18597 has progressed. Feel free to close this out.