"Install 2D Sprite Package" button in Sprite Renderer is disabled when no Sprite is assigned, contradicting its own help text

Steps to reproduce:

1. Create a new 3D project
2. Create an empty GameObject in the Hierarchy
3. In the Inspector, Add Component > Sprite Renderer
4. Observe the help box and the "Install 2D Sprite Package" button while no Sprite is assigned
5. Assign any Sprite to the Sprite field

Actual results: With no Sprite assigned, the help box instructs the user to "Click on the 'Install 2D Sprite Package' button to install the package", but that button is greyed out / disabled

Expected results: The "Install 2D Sprite Package" button should be enabled

Reproducible with versions: 6000.0.0f1, 6000.3.17f1, 6000.4.10f1, 6000.5.0b11, 6000.6.0a6

Tested on (OS): Ubuntu 24.04, macOS 26.5

Notes:

• Button only becomes enabled once a Sprite is assigned