[ML] Transforms: Add performance journey for transform wizard source index loading.

[walterra]

Summary

Part of #160712.

Add a performance journey for transform wizard source index loading.

node scripts/run_performance.js --journey-path x-pack/performance/journeys/many_fields_transform.ts

Journey showing up in APM:

Journey showing up in Performance Metrics:

Checklist

• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/ml-ui (:ml)

[peteharverson]

Great job adding in our first performance journey! LGTM

[dmlemeshko]

Thank you for the fix. I need to run a few pipelines to make sure we are able to extract APM transactions for scalability test simulation

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: be80b2b

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
transform	359	363	+4

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
transform	404.2KB	404.5KB	+325.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
enterpriseSearch	14	16	+2
securitySolution	413	417	+4
total			+6

Total ESLint disabled count

id	before	after	diff
enterpriseSearch	15	17	+2
securitySolution	492	496	+4
total			+6

History

• 💚 Build #139076 succeeded 00b08a1
• 💚 Build #139011 succeeded 3fd1d34
• 💔 Build #139003 failed e088cb4

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

cc @walterra

[dmlemeshko]

nice one! Having a single value for each metric per run seems the best way to go at the moment.

[mistic]

Dima commented he is going to validate the apm transaction thing.

The rest lgtm on the operations side

[dmlemeshko]

LGTM. Great work!