Comment Moderation Exp: Add toggle to enable/disable guest comments automatic moderation

[Intenzi]

What?

Closes #750

Adds a checkbox in Comment Moderation Experiment settings.

This allows enabling/disabling of the comment moderation flow (AI sentiment, toxicity analysis) when the comment user is anonymous.

Set to true/Enabled by default.

Why?

This is in continuation to #516 (comment)

It solves the problem of AI analysis being run on unwanted guest users/ spam of guest comments that can cause a Denial Of Wallet attack.

Additionally enables customization to moderation flow for the website's comment moderators.

How?

• Registers a settings field of the id moderate_guests as a boolean field. Enabled by default.
• When disabled, skips the AI sentiment, toxicity analysis for anonymous user comments.
• Copied structure of Content_Classification.php for settings registration.
• Additionally increased margin top spacing of inline settings form. This is to prevent the checkbox from looking squeezed in with the experiment's description.

Use of AI Tools

AI assistance: Yes
Tool(s): Antigravity
Model(s): Gemini 3.5 Flash (Low)
Used for: Identifying the css file for the css fix, adding the integration tests.

Testing Instructions

1. Enable Comment Moderation Experiment.

a> With Moderate Guest Comments settings field toggled on:

• Add a comment as a guest user after logging out / on incognito / etc.
• Go to Comments section in wp-admin and view that the comment has sentiment, toxicity analysis performed on it.

b> Turn off the Automatically moderate guest comments settings field by clicking on it:

• Add a comment as a guest user after logging out / on incognito / etc.
• Go to Comments section in wp-admin and observe that the comment does not have sentiment, toxicity analysis performed on it.

Screenshots or screencast

New Automatically moderate guest comments settings field enabled by default:

The setting field, toggled off:

Comments added when the setting was toggled off, on.

Changelog Entry

Added - Automatically moderate guest comments settings field which skips guest comments moderation when disabled.
Changed - Top margin spacing increased in inline settings form.

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Co-authored-by: Intenzi <intenzi@git.wordpress.org>

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