Add kibana client API wrappers for tamper protection E2E support

[aleksmaus]

What does this PR do?

Add kibana client API wrappers for tamper protection E2E support

• Added is_protected property to AgentPolicyUpdateRequest. This allows to enabled and disabled tamper protection through the policy update Kibana API
• Added GetPolicyUninstallTokens, that allows to to fetch uninstall tokens for tamper protected policy.
• Added DeleteFleetPackage. Is needed for testing of Endpoint tamper protection E2E.
• Moved InstallFleetPackage from https://github.com/elastic/elastic-agent/blob/main/pkg/testing/tools/fleet_package_policy_api.go#L66. Addresses that TODO item.
• Expanded integration tests for the newly introduced API.
  Was not sure if the current integration tests are ran in CI, but it was convenient to have some coverage and tests the APIs.

Why is it important?

These new additions are needed for Agent/Endpoint tamper protection E2E tests.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.md

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2023-08-01T16:24:20.373+0000

• Duration: 10 min 56 sec

Test stats 🧪

Test	Results
Failed	0
Passed	791
Skipped	13
Total	804

🤖 GitHub comments

Expand to view the GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 08c7670

History

• 💔 Build #32 failed 04b3b28
• 💔 Build #31 failed 3b37aae
• 💔 Build #30 failed b143f1e
• 💔 Build #29 failed 189862e
• 💔 Build #28 failed 5adb648
• 💔 Build #27 failed f722df1

[cmacknz]

Thanks! Is https://github.com/elastic/elastic-agent/blob/main/pkg/testing/tools/fleet_package_policy_api.go getting removed when this merges?

[aleksmaus]

Yeah, saw the "TODO" there and addressed along with other new additions that were needed for agent tampering test cases. Will pull these from the library once it merges and update agent E2E tests.