Mobile Accessibility: Fix ARIA role usage on admin bar icons when creating new post

[rollybueno]

An accessibility issue was found in the admin bar when creating a new post in mobile. The error, "Uses ARIA roles on incompatible elements," indicates that ARIA roles are applied to elements that do not support them. This can to be corrected to meet accessibility best practices and improve compatibility with assistive technologies.

To reproduce:

• Open Lighthouse
• Go to any posts and edit
• Make sure you select Mobile in Device option and Accessibility category
• Run the Accessibility scan.

Mobile Accessibility: Fix ARIA role usage on admin bar icons when creating new post

Trac ticket: https://core.trac.wordpress.org/ticket/63542

[opurockey]

After fix:

[joedolson]

Thanks for your report! However, this is a known false positive in Lighthouse. This was previously reported in #61795, and is not actually an accessibility error. It is an incorrect result in the Lighthouse test results; it is correct per the ARIA specifications.

This is a false report from Lighthouse and has been closed since https://core.trac.wordpress.org/ticket/63542#comment:3.

You can close this PR as well.