Steps to reproduce:

1. Create a new HDRP project, or open an existing one
2. Create a new material
3. Expand the Emission Inputs header
4. Notice that the Global Illumination enum list is missing

Notes:

- This is a regression in functionality when compared to built-in RP. In built-in RP, we offered three options:
* None. Emission does not contribute neither to real-time nor baked GI. This useful in cases where users rely on bloom to achieve certain effects.
* Baked. Emission contributes only to baked GI.
* Realtime. Emission contributes only to real-time GI.