The Deep Dark biome can generate way above deepslate layer

The Deep Dark biome can generate far above deepslate layer. This can pose an issue for those who want to avoid exploring the Deep Dark, but end up encountering it in non-deepslate caves anyway.

To reproduce, use the seed -3945541560037994869 and run the following command:

/execute in minecraft:overworld run tp @p 999 43 123