feat: #3622820 Refine the Newsletter page to the Educare design

Follow-up on the Newsletter page merged in !67 (merged), after a design review.

The page now reads the Educare way and the icons actually render.

What changed

• Heading is Stay informed; the lead text is shortened and given an explicit text_color so it does not inherit an unreadable colour.
• The three benefit cards are icon cards built from the registered icon SDC. The icons were previously written as markup, and canvas_html_block allows only <strong> <em> <u> <a> <p> <br> <ul> <ol> <li> — so the markup was stripped and the labels ran together on the rendered page.
• Component tree entries are written in the same key order as every other shipped page.
• No component versions are pinned, matching all 215 SDC components across the shipped pages. A pinned hash fails a fresh install with component_version=... is not a version that exists on ....

How it looks

Testing

Verified on a fresh Drupal CMS 2.1.4 install with the Educare site template picked in the browser installer:

• /newsletter returns 200 and the page renders with zero Canvas render errors.
• The footer Subscribe button lands on /newsletter.
• The subscribe form submits and stores the submission.
• The email field and the Subscribe button are the same height (58/58 desktop, 56/56 mobile) once varbase_webform_base!18 (merged) is in.

Issue: https://www.drupal.org/project/educare/issues/3622820

AI-Generated: Yes

Checkpoints:

• File an issue
• Addition/Change/Update/Fix
• Testing to ensure no regression
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• Automated functional testing coverage
• UX/UI designer responsibilities
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• Developer Documentation
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• Reviewed by human
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• Full testing and approval
• Credit contributors
• Review with the product owner
• Release notes snippet
• Release