Add "model alerts indicator" component

[shati-patel]

Adds "alert indicators" in the model editor to show how many results a certain model has generated:

• We only show these indicators when there's an evaluation run available
• Eventually these indicators will link to a separate model alerts view with more details
• We don't currently have any way of knowing which models are responsible for which alerts (see "alert provenance" work), so we just show a random number for now 🙃

Checklist

N/A, this is feature-flagged for internal use/testing 🎏

• [ ] CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• [ ] Issues have been created for any UI or other user-facing changes made by this pull request.
• [ ] [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.

[robertbrignull]

As an alternative suggestion for the columns, we go with having the alert count and the add/remove modeling icon in one column using a flex-box row. I think it should all work ok and then when the alert count badge isn't there we won't get an extra gap. I my mind, merging those two columns should be ok because they're both constant-width items and both set to max-content in the gridTemplateColumns.

I think you originally had a go at this and perhaps it didn't work or got a bit confusing, but I'm happy to help out if you want to try it again.

[shati-patel]

I think you originally had a go at this and perhaps it didn't work or got a bit confusing, but I'm happy to help out if you want to try it again.

Thanks! Will have another go (and potentially pester you for some more assistance 😄)