fix: restore newsletter form visual feedback and state management (#1978)

[rish0000-dot]

PR Description

This PR resolves Issue #1978 where the newsletter subscription form in the footer of the web platform appeared unresponsive after clicking "Subscribe".

Key improvements:

• Added interactive loading feedback (spinning SVG loader inside button) during state transition (newsletterStatus === "sending").
• Added inline validation error styling (.footer-subscribe-input--error) for empty or malformed email inputs.
• Replaced font icon dependencies with lightweight inline SVGs to ensure icons load reliably in all environments.
• Added accessibility improvements including aria-invalid, role="alert", and role="status" tags.
• Refactored web/src/components/ui/footer.tsx to delegate to NewsletterForm.tsx, preventing duplicate component logic.

Type of Change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update

Select your work-area

• Frontend
• Backend
• Documentation
• Others

Related Issue

#1978

Add your Work Example

(Optional: Attach a screenshot or GIF of the subscribed / loading state if available)

Fixes (mention the issue number which this fixes)

Closes #1978

Checklist

• I have updated my branch and synced it with the project's 'main' branch before making this PR.
• I have optimized the file changes.
• I have added a snapshot of my work example.
• I have made a PR to the project's target branch.

Undertaking

• My code follows the style guidelines of this project.

• I have performed a self-review of my code.

• I have commented my code, particularly in hard-to-understand areas.

• I have me corresponding changes to the documentation.

• I have checked for plagiarism and assure its authenticity.

• I have read and followed the code of conduct for this repository. I understand that violation of this undertaking may have legal consequences.

• I Agree

[github-actions]

Thank you @, for creating the PR and contributing to our UltimateHealth project 💗.
Our team will review the PR and will reach out to you soon! 😇
Make sure that you have marked all the tasks that you are done with ✅.
Thank you for your patience! 😀

[SB2318]

@rish0000-dot Thanks for your contribution, But this web related issue.

The work should be done in origin/web branch. 😇