[Flaky Test Handling] Drop scout from the report-flaky-tests pipeline name

[csr]

Summary

Removes scout from the name of the report-flaky-tests pipeline added in #289870. The report covers flaky tests from every framework (Scout, Jest, FTR, Cypress), so the name gave the wrong impression.

• kibana / scout / report-flaky-tests → kibana / report-flaky-tests (slug kibana-report-flaky-tests)
• .buildkite/pipeline-resource-definitions/kibana-scout-report-flaky-tests.yml → kibana-report-flaky-tests.yml
• .buildkite/pipelines/scout_report_flaky_tests.yml → report_flaky_tests.yml
• .buildkite/scripts/steps/scout_report_flaky_tests.sh → report_flaky_tests.sh
• .github/CODEOWNERS: @elastic/appex-qa @elastic/kibana-operations own these files (and check_flaky_test_issues.sh, the second step added in [Flaky Test Handling] Add check_flaky_test_issues CLI to find existing failed-test issues for flaky suites #290095), so either team can approve pipeline changes

[infra-vault-gh-plugin-prod]

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[github-actions]

One non-blocking note on the CODEOWNERS change: a new ownership entry references a Buildkite step script that doesn't exist in the repo yet. The pipeline/script/resource renames themselves are consistent — file paths, the pipeline slug, pipeline_file, sparse-checkout paths, and the locations.yml link are all updated together, and the renamed shell script has no lingering references to the old names.

Generated by Claude Reviewer for #290465 · claude · opus · 221.6 AIC · ⌖ 25.9 AIC · ⊞ 5.5K

[github-actions]

This ownership entry points to a path that doesn't exist in the repo yet. Unlike the three entries above it (which map to files renamed in this PR), .buildkite/scripts/steps/check_flaky_test_issues.sh is present neither on main nor at this PR's head. The description attributes it to #290095, but that PR is still open (unmerged) and adds the node scripts/check_flaky_test_issues CLI — not this Buildkite step — so the rule is inert and matches nothing until a future PR adds the script.

Not CI-breaking (the CODEOWNERS check regenerates the file and verifies teams; both teams are valid), but the entry is dead until the file lands, and it will silently rot if the eventual script is named or located differently. Consider adding this line in the PR that actually introduces the file, or confirm the final path before landing it here.

[csr]

This is correct - I will merge this PR after #290095 (which contains the new file) is in.

[kibanamachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 3b6eb90
• Build duration: 31 mins

Metrics [docs]

Unknown metric groups

warm start memory

id	before	after	diff
post forced gc heap baseline	-	839815028	+839815028
post forced gc heap delta	-	-1939024	-1939024
post forced gc heap delta standard deviation	-	1471591	+1471591
post forced gc heap target	-	837876004	+837876004
tail heap delta	-	7797855	+7797855
total			+1685021454

cc @csr