Add Template modal in Mobile Safari has layout issues - WP 6.6 #64769

Description

In WP 6.6, the Add Template module is off-center and cropped improperly on mobile Safari.

Step-by-step reproduction instructions

1. In mobile Safari, open the dashboard of a site on WP 6.6 with Gutenberg active or inactive
2. Open Appearance > Editor > Templates
3. Select Add New Template

Screenshots, screen recording, code snippet

Environment info

Tested on iOS 17.5.1

When you revert to WordPress 6.5.5, the Appearance > Editor > Templates page does not offer an Add Template button at all

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes