[Serverless Search Plugin] Migrate authc.getCurrentUser usage to coreStart.security

[tsullivan]

Part of https://github.com/elastic/kibana/issues/186574

Summary

This PR migrates the method to access a Serverless Search view model field, which consumes authc.getCurrentUser, to use coreStart.security.

Background: This PR serves as an example of a plugin migrating away from depending on the Security plugin, which is a high priority effort for the last release before 9.0.

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

[tsullivan]

/ci

[kibana-ci]

:yellow_heart: Build succeeded, but was flaky

• Buildkite Build
• Commit: f36108a0a70c758b5f885934b5590724aaff7cb4

Failed CI Steps

Metrics [docs]

Page load bundle

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

id	before	after	diff
serverlessSearch	20.6KB	20.6KB	-6.0B

Unknown metric groups

References to deprecated APIs

id	before	after	diff
serverlessSearch	3	2	-1

History

• :green_heart: Build #218577 succeeded 19d0d33fc9c3187d79a696a914ec5bff9009d708

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

[elasticmachine]

:green_heart: Build Succeeded

• Buildkite Build
• Commit: cd55005119d42a5ceb01d1ada8e803b530becc1d

Metrics [docs]

Page load bundle

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

id	before	after	diff
serverlessSearch	20.6KB	20.6KB	-6.0B

Unknown metric groups

References to deprecated APIs

id	before	after	diff
serverlessSearch	3	2	-1

[sphilipse]

For your reference we migrated (almost) all the other getCurrentUser calls here: https://github.com/elastic/kibana/pull/184762