[UX Dashboard] Move core web vitals query from APM routes to UX plugin

[justinkambic]

Summary

I closed #132755 in favor of opening a new PR as I accidentally pinged half of engineering. If you'd approved that PR you should feel confident in this one. The only change is the addition of an e2e test.

Related to #454.

Moves CWV query/fetch logic entirely to UX plugin.

Checklist

Delete any items that are not applicable to this PR.

• Unit or functional tests were updated or added to match the most common scenarios

Risk Matrix

Delete this section if it is not applicable to this PR.

Before closing this PR, invite QA, stakeholders, and other developers to identify risks that should be tested prior to the change/feature release.

When forming the risk matrix, consider some of the following examples and how they may potentially impact the change:

Risk	Probability	Severity	Mitigation/Notes
Multiple Spaces—unexpected behavior in non-default Kibana Space.	Low	High	Integration tests will verify that all features are still supported in non-default Kibana Space and when user switches between spaces.
Multiple nodes—Elasticsearch polling might have race conditions when multiple Kibana nodes are polling for the same tasks.	High	Low	Tasks are idempotent, so executing them multiple times will not result in logical error, but will degrade performance. To test for this case we add plenty of unit tests around this logic and document manual testing procedure.
Code should gracefully handle cases when feature X or plugin Y are disabled.	Medium	High	Unit tests will verify that any feature flag or plugin combination still results in our service operational.
See more potential risk examples

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/uptime (Team:uptime)

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)

[sorenlouv]

lgtm

[kibana-ci]

💚 Build Succeeded

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• Commit: dd53a1c
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Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
ux	142	144	+2

Async chunks

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

id	before	after	diff
ux	157.6KB	162.1KB	+4.5KB

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
ux	5.7KB	5.8KB	+66.0B

History

• 💛 Build #50019 was flaky f85cae7

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

cc @justinkambic