…leet!` FTR api tests (elastic#250075)

## Summary

This PR fixes the flakiness around creating an Endpoint package policy
using `endpointPolicyTestResources.createPolicy()`.

When an Endpoint package policy is created, the default rules are
installed in the background, which process can be flaky, or, together
with other functionalities, simply too slow (i.e. taking more than 2
minutes, causing `socket hang up` error). Therefore, there's a
workaround by the Detections team to install a mock
`security_detection_engine` package. This fix workaround is applied in
the EDR API tests as well.

For more info, see the original workaround PR:
- elastic#227689

Flaky runner: 25/25 ✅ for all 6 test groups:
- artifacts ESS + serverless
- artifacts with Endpoint exceptions moved FF enabled ESS + serverless
- spaces ESS + serverless

https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/10576/steps/canvas

fix elastic#249780
fix elastic#249463
fix elastic#249468
fix elastic#248923
fix elastic#248759
fix elastic#248578
fix elastic#248554
fix elastic#247416
fix elastic#247211
fix elastic#246564
fix elastic#246341
fix elastic#246450
fix elastic#246356
fix elastic#246207

### Checklist

Check the PR satisfies following conditions.

Reviewers should verify this PR satisfies this list as well.

- [x] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed

(cherry picked from commit d36d440)