[Prod] Fix markup (Accessibility improvements)

[thewatermethod]

Description of change

• Change heading level of user name in the avatar dropdown
• Add a screen reader only tag to the Supporting Attachments actions header
• Remove empty list item from semantic tree in avatar menu
• Confirm empty list item in usa-modal footer is not an accessibility issue
• Update aria label on delete file modal to be more succinct
• Remove h4 from drawer component when title is absent

How to test

• Confirm that the user menu and the avatars in the header and on the account management page still look and function correctly and that the heading is an appropriate level (h2)
• Confirm that deleting files still works correctly and that there are no empty cells in the file table
• Confirm that the drawers still look correct.

Issue(s)

• https://jira.acf.gov/browse/TTAHUB-3436

Checklists

Every PR

• Meets issue criteria
• JIRA ticket status updated
• Code is meaningfully tested
• Meets accessibility standards (WCAG 2.1 Levels A, AA)
• API Documentation updated
• Boundary diagram updated
• Logical Data Model updated
• Architectural Decision Records written for major infrastructure decisions
• UI review complete

Before merge to main

• OHS demo complete
• Ready to create production PR

Production Deploy

• Staging smoke test completed

After merge/deploy

• Update JIRA ticket status