[Monitoring] Initial setup mode with metricbeat migration is broken

[chrisronline]

Tested this on master

I'm not sure when this happened, but if you load up a fresh ES and try and enable metricbeat-based monitoring, the page doesn't load due to a client side error.

The issue is https://github.com/elastic/kibana/blob/master/x-pack/legacy/plugins/monitoring/public/components/elasticsearch/nodes/nodes.js#L89 is now throwing an error for a non-existing . nodeTypeLabel (which doesn't exist when we fetch the live ES node for metricbeat migration setup mode)

I'm not sure what changed recently around this. https://github.com/elastic/kibana/pull/51100/files#diff-2b7cce7f9c72c72b15f65c30b0aeb499 looks like a superficial change, but perhaps something changed on the EUI side.

[elasticmachine]

Pinging @elastic/stack-monitoring (Team:Monitoring)

[chrisronline]

@igoristic Can you take a look at this?