Misaligned dashicon for Add media menu in mobile viewport

[joedolson]

The menu toggle when creating galleries or mixed-model content in the media modal has too much line-height on the icon.

Fixes mobile viewport media menu alignment

Trac ticket: https://core.trac.wordpress.org/ticket/64726

## Use of AI Tools

[huzaifaalmesbah]

Patch Testing Report

Patch Tested: ​https://github.com/WordPress/wordpress-develop/pull/11052

Environment

• WordPress: 7.0-beta1-61709-src
• PHP: 8.2.29
• Server: nginx/1.29.5
• Database: mysqli (Server: 8.4.8 / Client: mysqlnd 8.2.29)
• Browser: Chrome 145.0.0.0
• OS: macOS
• Theme: Twenty Eleven 5.0
• MU Plugins: None activated
• Plugins:
  • Classic Editor 1.6.7
  • Test Reports 1.2.1

Steps taken

1. Resized viewport to mobile width (~375–480px).
2. Opened Posts → Add New.
3. Clicked Add Media.
4. Observed dashicon alignment in the media modal menu before patch.
5. Applied ​PR #11052.
6. Re-tested in mobile viewport.
7. ✅ Patch is solving the problem

Expected result

• Dashicon vertically centered in the toggle button.
• No extra line-height spacing.
• Proper alignment in mobile viewport.

Screenshots

Before	After ✅

[joedolson]

The patch is one line of CSS, so I think I'll consider one test to be sufficient.

Marking for commit.

[joedolson]

In 61744:

Media: Fix misalignment in media panel mobile menu.

Adjust the line-height of the dashicon for the media panel mobile menu.

Props huzaifaalmesbah, joedolson.
Fixes #64726.