Closes #26750: add Wallpapers Onboarding dialog

[mavduevskiy]

Closes #26750

Pull Request checklist

• Tests: This PR includes thorough tests or an explanation of why it does not
• Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features. In addition, it includes a screenshot of a successful accessibility scan to ensure no new defects are added to the product.

QA

• QA Needed

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GitHub Automation

Fixes #26750

[mergify]

This pull request has conflicts when rebasing. Could you fix it @mavduevskiy? 🙏