Show the generator of the selected Media Library tab when it is still loading

Problem/Motivation

In CKEditor Insert Media, clicking SVG Image and then Generate with AI before the SVG tab loaded shows the Image generator under the SVG tab, and an image is made.

Steps to reproduce

1. Open Insert Media in CKEditor.
2. Click a media type tab and at once click Generate with AI.

Proposed resolution

The switch waits for or cancels the pending tab request, and the server builds the generator for the type the request names.

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): after a quick tab change, the SVG Image tab shows the Image generator.
  
• After: the SVG Image tab shows its own generator.
  

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• N/A

AI-Generated: Yes