Steps to reproduce:

1. Create a new or open an existing project
2. Navigate to Lighting Settings window and click on Generate Lighting
3. Back in the scene view, select Baked Lightmap debug view mode
4. Try either typing in the values in the float field or using the slider in the Baked Lightmap Exposure gizmo
5. Notice that the exposure values don't change

Notes:

- Clicking on the slider works, but sliding it does not
- Affects all render pipelines
- Reproduces in: 2020.1.0a24, 2020.1.0a25, 2020.1.0b1
- Not reproducible in: 2020.1.0a23, 2020.1.0a1