Update usetesting configuration in golangci-litn

[mstoykov]

With #4604 we started using usetesting instead of tenv as a linter.

It configuration has more configuration that can be used, and maybe we do not need it at all 🤷 .

As a point for tenv ever being used can be to prevent people from using os.SetEnv at all in the first place. Although I am pretty sure this is now done in other ways as well.