[Security Solution][Detection Engine] fixes 410 error on index legacy template call

[vitaliidm]

Summary

_template API is blocked on Serverless, causing 410 error when creating list index.

This _template API is used to check existing legacy index templates for lists and items indices

So, in this PR, we won't be throwing error if any of _template APIs called in Serverless environement and return 410 code error(Gone)

[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: 1b2377a

Failed CI Steps

• Serverless Security Cypress Tests #8
• Security Solution Cypress Tests #9

Test Failures

• [job] [logs] Security Solution Cypress Tests #9 / Cases Creates a new case with timeline and opens the timeline Creates a new case with timeline and opens the timeline

Metrics [docs]

✅ unchanged

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

cc @vitaliidm

[e40pud]

LGTM! So this is kind of the way to check whether we run on Serverless? Is there any other way to do that?

[vitaliidm]

LGTM! So this is kind of the way to check whether we run on Serverless? Is there any other way to do that?

I don't think we do any checks for environment. Code should be environment agnostic in general and work depends on configuration. In that case handling 410 error is kind of similar to 404 - resource/endpoint do not exist, so we continue execution of parent function w/o throwing error. It's a legacy index template, that won't ever exist in Serverless and should be gradually removed from Stateful, if present.