HDRP: Enable both Light Layers and Decal Layers breaks Visual Environment on Skinned Mesh Renderers

1. What happened

When Light Layers and Decal Layers are both enabled on the HDRP Render Pipeline Asset, the visual environment in the scene breaks, and the lighting goes very dark on Skinned Mesh Renderers. This is a regression from 2021.3.7.

2. How can we reproduce it using the example you attached

• Open OutdoorsScene, and switch to the Game View. Notice that the "Y Bot" model is reasonable well lit.
• Open Assets/Settings/HDRP High Fidelity asset
• Under Rendering, go to the Decals section, and enable the "Layers" checkbox.
• Note that the "Y Bot" model is now very dark, and barely lit.
• Now notice that if you uncheck Lighting -> Light Layers, the rendering is corrected.

The error only appears to occur when both Light Layers and Decal Layers are enabled. If neither, or only one, is enabled, the lighting looks correct. This was not happening in 2021.3.7, and appears to be a regression in all the HDRP changes under 2021.3.9.