Kibana version:
tested with kibana-7.8.1-windows-x86_64 and kibana-7.9.0-windows-x86_64

Elasticsearch version:
tested with elasticsearch-7.8.1 and elasticsearch-7.9.0

Server OS version:
tested on windows 10

Browser version:
chrome Version 84.0.4147.125 (Official Build) (64-bit)

Browser OS version:
tested on windows 10

**Original install method (e.g. download

Hi guys,

I just heard about this repo, and so I was going through the docs and clicking around, and I got incredibly frustrated by 2 things:

window.alert

In Button, I don't understand why each button needs to trigger an alert, which also breaks the purpose of the demo since you don't get to see the full component animation? And for each button that you try out, you add an extra click s

Following up #3387 we should add a validation to check that node.roles is only set for ES >= 7.9.0.
The reason is that once our quickstart is updated some users might blindly downgrade the Elasticsearch version, it might help the user to immediately surface this error.

Related to #3324