Give the AI tabs in the Media Library a clean accessible name

Problem/Motivation

An AI tab's accessible name is "Show Generate image with AI media , new": core's "Show ... media" wraps the AI label and the badge.

Steps to reproduce

1. Open the Media Library with a screen reader.
2. Focus an AI tab.

Proposed resolution

Give the AI tab link a clean accessible name: "Generate image with AI, new".

Remaining tasks

• ✅ File an issue
• ❌ Addition/Change/Update/Fix
• ❌ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support
• ➖ User Guide Documentation support
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ❌ Reviewed by a human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ✅ Update Release Notes
• ✅ Release

User interface changes

• Before (1.0.x, Gin): the AI tab is read as "Show Generate image with AI media , new".
  
• After (Gin): the tab looks the same and is read as "Generate image with AI, new".
  

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• N/A

AI-Generated: Yes