[8.x] [Migrations] Backport ALL updates to integration tests

[gsoldevila]

Backport

This will backport the following PRs from main to 8.x:

• [Migrations] Provide testing archives + tooling for migrations integration tests #193328
• [Migrations] Fix integration tests that use ZIP archives that are not compatible with 9.0.0 #193856
• [Migrations] Upgrade tests to use 9.x compatible archives #193696
• [Migrations] Upgrade integration tests - follow up work #194151

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: b510064

Failed CI Steps

Metrics [docs]

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
@kbn/test	267	268	+1

Unknown metric groups

API count

id	before	after	diff
@kbn/test	315	316	+1

History

• 💔 Build #237364 failed 69df580
• 💔 Build #237287 failed 8dde14e

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

cc @gsoldevila