Focus border styling breaks slug input layout in Classic Editor

[dhruvang21]

While testing the changes introduced in PR: ​https://github.com/WordPress/wordpress-develop/pull/11551, I came across a UI issue in the Classic Editor related to the post slug (permalink) editing field.

When the slug input receives focus, the focus border appears larger than expected and causes the layout to break.

Steps to Reproduce:

• Go to Posts → Add New (or edit an existing post)
• Click on the permalink “Edit” button
• Focus on the slug input field
• Observe the input field styling

Expected Behavior:
The focus state should not alter the layout or dimensions of the input field. The slug field should remain properly aligned within its container.

Actual Behavior:
On focus:

• The border/outline appears thicker or offset
• The input visually overflows or misaligns
• The slug field appears “broken” within the layout

[joedolson]

I wouldn't agree that the focus is causing a misalignment; but the bottom edge of the focus state is being hidden, resulting in an unexpected appearance.

This is not an accessibility issue; the focus state is still adequate for accessibility purposes, so I'm removing the accessibility keyword. I'll take ownership, anyway, however.

This PR fixes:

1. The box shadow on focus the input of edit slug on classic editor.
2. the OK button alignment on editing the slug on classic editor.

Trac ticket: https://core.trac.wordpress.org/ticket/65071