[Security Solution] Fix rule severity sorting in inMemory tables

[jpdjere]

Summary

• Fix rule severity sorting in in-memory tables (Add Rules table and Rule Upgrade table) so that rows are filtered by the semantic meaning of severity.

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• Any UI touched in this PR is usable by keyboard only (learn more about keyboard accessibility)
• Any UI touched in this PR does not create any new axe failures (run axe in browser: FF, Chrome)
• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• This renders correctly on smaller devices using a responsive layout. (You can test this in your browser)
• This was checked for cross-browser compatibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/security-detections-response (Team:Detections and Resp)

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 69b4824

Failed CI Steps

• Investigations - Security Solution Tests #2
• Investigations - Security Solution Tests #4

Test Failures

• [job] [logs] Investigations - Security Solution Tests #4 / Alerts generated by building block rules Alerts should be visible on the Rule Detail page and not visible on the Overview page
• [job] [logs] Investigations - Security Solution Tests #2 / Detection response view Open in timeline "after each" hook for "opens timeline with correct query count for open alerts by rule table"
• [job] [logs] Investigations - Security Solution Tests #2 / Detection response view Open in timeline opens timeline with correct query count for open alerts by rule table

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
securitySolution	11.0MB	11.0MB	+189.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	13	15	+2
securitySolution	411	415	+4
total			+6

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	14	16	+2
securitySolution	494	498	+4
total			+6

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @jpdjere

[xcrzx]

LGTM, thanks for the fix, @jpdjere 👍