task: Remote feature flag gates GutenbergKit

[dcalhoun]

Augment the existing, user-controlled experimental feature toggle with a remote feature flag that can we used for a phased roll out GutenbergKit regardless of the experimental feature toggle state.

To Test:

A remote feature flag has not yet been deployed on the server, so there should be no changes to the UX.

Regression Notes

1. Potential unintended areas of impact
   Unlikely for this addition.
2. What I did to test those areas of impact (or what existing automated tests I relied on)
   N/A.
3. What automated tests I added (or what prevented me from doing so)
   Deemed unnecessary for the experimental feature.

PR Submission Checklist:

• I have completed the Regression Notes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

Testing Checklist (strike-out the not-applying and unnecessary ones):

• WordPress.com sites and self-hosted Jetpack sites.
• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• Talkback.
• Languages with large words or with letters/accents not frequently used in English.
• Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• Large and small screen sizes. (Tablet and smaller phones)
• Multi-tasking: Split screen and Pop-up view. (Android 10 or higher)

[dangermattic]

	2 Warnings
⚠️	Class GutenbergKitFeature is missing tests, but unit-tests-exemption label was set to ignore this.
⚠️	PR is not assigned to a milestone.

Generated by 🚫 Danger

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr21810-92a416a
	Commit	92a416a
	Direct Download	jetpack-prototype-build-pr21810-92a416a.apk

Note: Google Login is not supported on these builds.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr21810-92a416a
	Commit	92a416a
	Direct Download	wordpress-prototype-build-pr21810-92a416a.apk

Note: Google Login is not supported on these builds.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 39.32%. Comparing base (7bc7243) to head (92a416a).
Report is 2 commits behind head on trunk.

Additional details and impacted files

@@           Coverage Diff           @@
##            trunk   #21810   +/-   ##
=======================================
  Coverage   39.32%   39.32%           
=======================================
  Files        2125     2125           
  Lines       99871    99871           
  Branches    15385    15385           
=======================================
  Hits        39277    39277           
  Misses      57114    57114           
  Partials     3480     3480           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[nbradbury]

Changes look good

[sentry-io]

Suspect Issues

This pull request was deployed and Sentry observed the following issues:

• ‼️ ApplicationNotResponding: ANR for at least 5000 ms. org.wordpress.android.fluxc.persistence.SiteSql... View Issue
• ‼️ ApplicationNotResponding: ANR org.wordpress.android.models.CategoryModel in d... View Issue

_{Did you find this useful? React with a 👍 or 👎}