Fixes Failing test: X-Pack Alerting API Integration Tests.x-pack/test/alerting_api_integration/spaces_only/tests/alerting/builtin_alert_types/index_threshold/alert·ts - alerting api integration spaces only Alerting builtin alertTypes index_threshold rule runs correctly: avg all

[ymao1]

Resolves #142335

Summary

This test failed very infrequently. It looks like the test was updated in this PR to also test that the index threshold gracefully handles ES errors, so it was testing two different things. I split this out into two separate tests in case they were interfering with each other somehow and increased the lookback for the average all test

Flaky test runner:

• https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/1514
• https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/1516

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)

[ymao1]

@elasticmachine merge upstream

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 3966940

Metrics [docs]

Unknown metric groups

ESLint disabled in files

id	before	after	diff
osquery	1	2	+1

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	19	21	+2
fleet	58	64	+6
osquery	108	113	+5
securitySolution	440	446	+6
total			+19

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	20	22	+2
fleet	66	72	+6
osquery	109	115	+6
securitySolution	517	523	+6
total			+20

History

• 💚 Build #85467 succeeded ce2330f
• 💚 Build #85176 succeeded 4e70ccb
• 💚 Build #84885 succeeded 0b977eb
• 💚 Build #84734 succeeded a507f1d
• 💚 Build #84660 succeeded 36f926b9c6722b7eed9b7292209e48d98a508a0d
• 💚 Build #84437 succeeded 9a9e15fbb0222526f01aa2d1394d500cee6424b7

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

cc @ymao1

[ersin-erdal]

LGTM