Outline/Underlay settings cannot be toggled on Legacy Font Asset Materials

Steps to reproduce:

1. Create and open a new project
2. Import the "CalibriBold.ttf" font into the project
3. Open 'Window -> Text -> Font Asset Creator'
4. Assign the imported font to 'Source Font' and press Generate Font Atlas
5. Expand the generated Font Atlas and select the material
6. In the Inspector, click on the Underlay or Outline checkboxes and observe

Actual results: The setting is not toggled

Expected results: The setting is toggled

Reproducible with versions: 6000.0.0f1, 6000.0.78f1 6000.3.18f1, 6000.5.2f1, 6000.6.0b1, 6000.7.0a1

Tested on (OS): Windows 11 Pro (25H2)

Notes:

• TextMeshPro-generated materials are not affected
• "Use Ratios" checkbox cannot be toggled on either legacy Font Asset, nor TextMeshPro materials