Properties used as a discriminator should be required

[tobio]

Summary

From the OpenAPI specification for discriminator properties:

This property SHOULD be required in the payload schema, as the behavior when the property is absent is undefined

Checklist

Check the PR satisfies following conditions.

Reviewers should verify this PR satisfies this list as well.

• 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
• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• This was checked for breaking HTTP API changes, and any breaking changes have been approved by the breaking-change committee. The release_note:breaking label should be applied in these situations.
• Flaky Test Runner was used on any tests changed
• The PR description includes the appropriate Release Notes section, and the correct release_note:* label is applied per the guidelines
• Review the backport guidelines and apply applicable backport:* labels.

[paul-tavares]

Looks good. Apologies for missing this when I initially made these changes

[kibanamachine]

Starting backport for target branches: 8.19, 9.1, 9.2

https://github.com/elastic/kibana/actions/runs/18762451057

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 851f718

Failed CI Steps

• FTR Configs #82

Metrics [docs]

✅ unchanged

History

• 💛 Build #353096 was flaky 6fb43f9

cc @tobio

[kibanamachine]

💔 All backports failed

Status	Branch	Result
❌	8.19	Backport failed because of merge conflicts You might need to backport the following PRs to 8.19: - [Fleet] Remove agent policies revision bump after updating settings (#239977)
❌	9.1	Backport failed because of merge conflicts You might need to backport the following PRs to 9.1: - [Fleet] Remove agent policies revision bump after updating settings (#239977)
❌	9.2	Backport failed because of merge conflicts

Manual backport

To create the backport manually run:

node scripts/backport --pr 239898

Questions ?

Please refer to the Backport tool documentation