New review comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/24620#discussion_r483943485

Comment:
This validation is incredibly fragile because the checksum is almost certain to change whenever Sublime changes something trivial like the navigation header. In a restricted package, we don't care about the contents of the license because we aren't distributing anything. There's no need to do any validation here.

I recommend just dropping `_license_checksum` and everything in this function except the `w3m` dump.