[Security Solution] Fixes siem upgrade assistant error when not all spaces have privilege

[dplumlee]

Summary

Addresses #164239

Checklist

Delete any items that are not applicable to this PR.

• Unit or functional tests were updated or added to match the most common scenarios

For maintainers

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

[elasticmachine]

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

[dplumlee]

@elasticmachine merge upstream

[kibana-ci]

💚 Build Succeeded

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• Commit: 8e32dbe
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Metrics [docs]

✅ unchanged

History

• 💔 Build #153238 failed 7f5404e
• 💚 Build #151625 succeeded 7816fa9
• 💔 Build #151624 failed 9fd0e86

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@elasticmachine merge upstream