[Fleet] Add functional tests for bundled packages

[kpollich]

Summary

Closes #124254

Add functional tests for a few installation/update cases around bundled packages:

• Baseline bundled installation behavior via API
• Update from bundled package to newer bundled package via API
• Update from bundled package to newer package from registry via API

Also includes some alterations to payloads coming from install APIs to include a _meta property with an install_source value. This allows us to easily assert on expected install sources in tests, but also provides likely valuable debugging information around these APIs.

Finally, this moves the bundled packages directory to fleet/target rather than a separate git ignored directory under fleet/server. This is consistent with other build artifacts, etc.

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[spalger]

LGTM

[nchaulet]

One small suggestion otherwise 🚀

[kpollich]

@elasticmachine merge upstream

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 1cc14e5
• Storybooks Preview
• Webpack Bundle Analyzer

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
fleet	1233	1235	+2

Unknown metric groups

API count

id	before	after	diff
fleet	1350	1352	+2

History

• 💔 Build #27099 failed af4f27d
• 💔 Build #27086 failed d5d869a
• 💔 Build #26973 failed a210c3e
• 💔 Build #26893 failed 4a29b44
• 💔 Build #26871 failed 1a2a2fd
• 💔 Build #26838 failed f3c266e

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

cc @kpollich

[kibanamachine]

💔 Backport failed

The pull request could not be backported due to the following error:
There are no branches to backport to. Aborting.

How to fix

Re-run the backport manually:

node scripts/backport --pr 126595

Questions ?

Please refer to the Backport tool documentation