[Fleet] [7.17] Backport optional validation results changes from #125068

[kpollich]

Summary

Some changes from #125068 weren't included in the 7.17 backport (likely due to conflicts), so this PR adds in those optional chaining changes based on cases where a package adds new policy templates between versions.

@andrewkroh Once this lands in 7.17, this should unblock elastic/integrations#2806

Screenshot

Demonstrating we can now successfully render the upgrade UI for CrowdStrike v1.4.0 -> 1.5.0

Testing instructions

1. Check out [crowdstrike] Create FDR and SIEM Connector policy templates integrations#2806 in your local integrations repo
2. In integrations, cd packages/crowdstrike && elastic-package build
3. From your local package-registry repo, copy the built 1.5.0 crowdstrike package, e.g. cp -r ../integrations/build/packages/log/1.0.1 ./build/package-storage/packages/log/1.0.1
4. Ensure your package registry's config.yml file includes - ./build/package-storage/packages under the package_paths key
5. Run the package registry, e.g. go run .
6. Set xpack.fleet.registryUrl: http://localhost:8080 in your config/kibana.dev.yml file
7. Start Kibana
8. Observe the 1.5.0 version of CrowdStrike is available in the integrations UI
9. Create a CrowdStrike integration policy under a prior version like 1.4.0
10. Install Crowdstrike 1.5.0
11. Upgrade your outdated CrowdStrike 1.4.0 policy
12. Note the conflicts on the required queue URL variable, and that the upgrade UI renders as expected

There's probably an easier way to test this using elastic package stack up but I haven't played around much with that tool yet. Feel free to comment if you use a different way to grab this development package and test the changes locally!

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 2a78f38
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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
fleet	628.9KB	629.0KB	+88.0B

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

cc @kpollich

[nchaulet]

@kpollich FYI with elastic-package you can run the registry like this from your package repository (and remove the step 3,4,5)

elastic-package stack up -s package-registry

and you can use https://localhost:8080 as package registry (you will have to provide custom CA for package registry: NODE_EXTRA_CA_CERTS=$ELASTIC_PACKAGE_CA_CERT yarn start --no-base-path)

[nchaulet]

Looks good to me 🚀