Bundled Theme: Fix scroll jump when closing modals in Twenty Twenty.

[SainathPoojary]

This PR addresses an issue where closing search modal (e.g., mobile menu or search) causes the page to briefly jump to the top and scroll back. The fix ensures smooth scroll restoration by:

• Using behavior: 'instant' in scrollTo for instant position restoration

Trac ticket: #52116

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions[bot]]

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Props sainathpoojary, nikunj8866.

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[github-actions[bot]]

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Test this pull request with WordPress Playground.

[SainathPoojary]

Before:

https://github.com/user-attachments/assets/935a7aca-e7f6-4476-bce4-15d6f4755b49

After:

https://github.com/user-attachments/assets/a8d5e63e-00c2-4cf0-ad80-dee538378484

[nikunj8866]

== Test Report This report validates that the indicated patch addresses the issue.

Patch tested: https://github.com/WordPress/wordpress-develop/pull/8461

=== Environment

• OS: Windows
• Web Server: Nginx
• PHP: 8.2.23
• WordPress: 6.7.2
• Browser: Chrome Version 134
• Theme: Twenty Twenty

=== Actual Results

• ✅ Issue resolved with patch.

=== Supplemental Artifacts Before Patch:

https://github.com/user-attachments/assets/ed00e54e-aed6-4974-b2b9-dfc8210bcf42

After Patch:

https://github.com/user-attachments/assets/a441d400-a200-4bf9-ac0c-f72556680d12

[github-actions[bot]]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 60280 GitHub commit: https://github.com/WordPress/wordpress-develop/commit/91a74b3af5d54226a9af39f0685268d89f5c2d8c

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.