added closing bracket on div tag for field image gallery

[nhjohnstone]

📝 Description

added closing bracket on div tag for field image gallery and cleaned up twig code

Fixes #1292

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✅ Peer Review Checklist

Reviewers: Please verify the following before approving.

• The pull request links to the issue it is addressing in the comment and in the "Development" section of the PR
• There is a short summary that describes how the fix is implemented
• Verifying work: Verify that the changes made are addressing the linked issue
• Accessibility: Changes that might impact accessibility are reviewed to work with keyboard navigation and screen readers
• Responsive: Layout is tested on desktop, tablet, and mobile screens
• Config changes: Any configuration updates are tested and verified using the Distribution Update import
• Security: Output is sanitized (using t(), Twig auto-escaping, etc.). No secrects included (API keys, etc.)
• Cleanliness: All debug code (ksm(), dpm(), console.log) has been removed.
• Comments: Complex logic is explained inline.
• Documentation: Any relevant documentation has been updated (this can be a separate issue if needed)

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📸 Screenshots / Video (Optional)

If this is a UI change, please attach a screenshot or a quick screen recording of the change in action.

[tjackson2113]

Addresses #1305 correctly. Attributes added via addClass.