[Fleet] Update max version supported of package spec to 3.5

[jsoriano]

Summary

9.2 will support package spec 3.5.

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.

Identify risks

• OTel input packages are expected to work with packages spec 3.5 and kibana 9.2, but its support is not complete yet. There are no OTel input packages in any case yet.

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[juliaElastic]

LGTM

[kc13greiner]

LGTM!

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: faf93ff

Failed CI Steps

• FTR Configs #51

Test Failures

• [job] [logs] FTR Configs #51 / security APIs - Session Lifespan Session Lifespan cleanup should properly clean up session expired because of lifespan when providers override global session config

Metrics [docs]

✅ unchanged

History

• 💛 Build #343266 was flaky 1d70f2b
• 💚 Build #341959 succeeded 2ca6d04

cc @jsoriano