Fix layout issues in publishing actions

[Infinite-Null]

https://core.trac.wordpress.org/ticket/65362

Description

This patch makes #major-publishing-actions to display: block and uses the float-based layout for #delete-action (left) and #publishing-action (right), which handles injected third-party content gracefully.

Before / After

Before	After

Testing Instructions

1. Install a plugin that injects content into the publish meta box (e.g., Yoast Duplicate Post).
2. Navigate to Posts → Edit on the Classic Editor screen.
3. Verify the Publish meta box renders without overlap:
   • "Move to Trash" appears bottom-left.
   • "Publish / Update" button appears bottom-right.
   • Any plugin-injected links stack above without breaking the layout.
4. Confirm the layout also looks correct on a vanilla install with no
   third-party plugins active.

[github-actions]

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[github-actions]

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Props ankitkumarshah.

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