Administration: Limit page jumping by scoping admin notice relocation

[wprashed]

Trac Ticket

https://core.trac.wordpress.org/ticket/65877
See also https://core.trac.wordpress.org/ticket/45186

Description

In src/js/_enqueues/admin/common.js, notice relocation after .wp-header-end previously used an un-scoped selector:

.not('.inline, .below-h2').insertAfter();

This matched and moved every notice found anywhere in the DOM—including contextual notices rendered inside .wrap, list tables, metaboxes, or forms—ripping them out of their authored positions and re-inserting them under .wp-header-end. On pages like edit.php, this resulted in unnecessary DOM mutation, reverse ordering, and sudden layout shifts (page jumping) as the user interacts with the post list.

The Fix

Scopes the selector to only move notices that are direct children of #wpbody-content:

    .not('.inline, .below-h2')
    .insertAfter();

• Only moves top-level notices that were rendered before .wrap by admin-header.php's admin_notices action hook.
• Preserves notices already positioned within .wrap or specific sub-containers, preventing redundant DOM repositioning and mitigating layout shift.

Fixes #65877.

[github-actions]

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Props wprashed, sadmansakibnadvi.

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[github-actions]

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[sadmansakibnadvi]

Tested this on the Playground build for the PR with a small test plugin (a notice nested inside a settings panel plus a normal admin_notices notice) and posted a full test report including the plugin code on the ticket. Short version: the nested notice now keeps its position inside the panel, and top-level admin notices still relocate under the page heading exactly as before.