There's a closed pull request on the void-packages repository

Fix nss/nspr dependencies
https://github.com/void-linux/void-packages/pull/31279

Description:
- I've seen at least two people in IRC asking about firefox not working correctly, both due to `nss`
- keeping track of when a new `nss` is required by firefox is very error prone
- there is one con, which is that `nss` reverts will require rebuilding firefox (I think)

I'm not sure rebuilding firefox is really necessary in this PR, so I can remove it.

@sgn @Duncaen 

[ci skip]