Unused Foliage Type Causing Unbuilt Lighting

Foliage components will be unbuilt even after deleting all of the placed foliage in a level.

Found in 4.20 CL# 4369336, 4.21 CL# 4753647, 4.22 CL# 4827620

1. Open the Editor
2. Create a foliage type out of any static mesh
3. Go to the foliage tool and add the foliage you created
4. Place a single instance of the foliage and build lighting
5. Using the select tool, select the single instance and delete it
6. Build lighting again

Results:
Any future lighting builds will have this unbuilt unused component even when all the placed foliage has been removed.

Expected:
Lighting will build with no errors