Precomputed AO Mask renders with value of zero after building lighting

Regression: Tested in UE5/Release-5.0 at CL 20979098, this issue does not occur so it is a regression. 

This issue occurs in 5.1 for both normal light building and GPU Lightmass building. In 5.0 the issue only occurs with GPU Lightmass building, the material will only render white when building light without GPU Lightmass.

1. Create a new Basic level
2. Set the Directional Light and SkyLight mobility to Stationary
3. In World Settings, enable Use Ambient Occlusion and Generate Ambient Occlusion Material Mask
4. Create a new material
5. Create a Precomputed AO Mask node and connect it to Base Color
6. Add a sphere to the level
7. Assign the new material to the sphere
8. Build lighting

Actual Result: Sphere renders as a black material being applied to it

Expected Result: Sphere should render white