[DataViews] Use client-side authc.getCurrentUser from core.security

[tsullivan]

Summary

Part of #186574

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. The Data Views plugin uses the authc.getCurrentUser method as a means to use the user's profile_uid for creating a user-hash which is sent as a field in the headers of a particular request.

What makes this example interesting: Data Views was not able to have a direct dependency on the Security plugin due to issues with a circular dependency. As a workaround, it used the coreSetup.plugins.onStart Promise to use Security services in a non-contractual way. The change in this PR does away with the workaround and allows Data Views to consume the Security service in a more typical way.

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

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[lukasolson]

Added a small PR that simplifies things a tad more here: tsullivan#12

[tsullivan]

/ci

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: c73e220

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
dataViews	402	401	-1

Page load bundle

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

id	before	after	diff
dataViews	61.6KB	61.3KB	-259.0B

Unknown metric groups

API count

id	before	after	diff
dataViews	1159	1158	-1

References to deprecated APIs

id	before	after	diff
dataViews	37	36	-1

History

• 💔 Build #218056 failed c7346e6f5177e026849d57b16ae1faa41fc02751
• 💛 Build #218021 was flaky 9297aa1fe7a1d08ba76f7f8d21d7676679cf6655
• 💔 Build #217998 failed 42c4978e0ec8c22e099854b53264090f6b5cbd1a
• 💔 Build #217997 failed 5e12337c59d10e8f8edf102744b938f48f7a5f54
• 💛 Build #217547 was flaky 548fcbe

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