How to reproduce:
1. Create a new Unity project
2. In Unity Cloud, create a new organization
3. Go to Window -> Package Management -> Package Manager -> "+" button -> Create Package 
4. Click "Export" and observe the "Authoring Org" dropdown options

Expected results: The new organization is visible there because it is already visible in the Project Settings and Hub
Actual results: New organization is not shown

Reproducible with: 6000.3.3f1, 6000.4.0b3, 6000.5.0a3
Can't test with: 6000.0.65f1 (No such functionality)

Reproducible on: macOS Tahoe 26
Not reproducible on: No other environment tested

Note: 
- Creating a new project after creating an organization doesn't solve an issue
- Restarting the project doesn't solve an issue
- Linking the project to the new organization doesn't solve an issue
- New organization also doesn't appear when editing the package in the Inspector