[Upgrade Assistant] Support "success" state on overview page

[alisonelizabeth]

The "Overview" page in Upgrade Assistant currently displays a list of steps using the EuiSteps component, all of which hard-code the state to "incomplete".

We should be able to determine whether each step is complete and update the UI accordingly with the following logic:

• Back up step is completed on Cloud when there are snapshots
• Reindex system indices will be completed when they’ve all been reindexed
• Fix issues step is completed when there are no critical warnings for ES or Kibana
• Fix logs step is completed when there are no logs since the last checkpoint

As part of this work, we should also update the UI when a user has 0 critical deprecations.

Proposed design:

[elasticmachine]

Pinging @elastic/kibana-stack-management (Team:Stack Management)

[cjcenizal]

I noticed that the es_stats.tsx and kibana_stats.tsx components are fairly divergent in terms of their logic, which adds some maintenance friction given that they behave identically. As part of this scope, let's also extract out the common logic into a shared stats_panel.tsx component or something similar.

UPDATE: Addressing this in #111231

[cjcenizal]

@dborodyansky Are we also planning on putting links inside of the panels? If so could we update the mockup?

[alisonelizabeth]

Are we also planning on putting links inside of the panels?

I think we originally had links (but in the top right corner). I don't remember the specifics now, but at one point in a review it came up that it might be easier for the user if the entire panel was clickable, which is why we switched to using EuiCard. I don't have a strong opinion either way, but just wanted to share some background.

[sabarasaba]

We indeed used to have a link on the top right corner. I think it looks much cleaner without any links, but the only problem I have with it is that the card is not treated as a link but as a div with an onClick event that navigates to a url. This means that when you hover the card you don't get a preview url from the browser and also breaks the cmd+click/ctrl+click to open the link in a new tab.

[dborodyansky]

Moving "links inside cards" discussion to #111041

[alisonelizabeth]

Addressed by #111243 and #111231