`javascript.validation.enabled` editor setting controls typescript validation as well

> For future travelers just in case it's useful, I had `"javascript.validate.enable": false` because I didn't want JS files specifically to be checked. Looks like with the native preview that setting is now interpreted as a blanket disabling of typescript checking across the board.

_Originally posted by @elramus in [#4587](https://github.com/microsoft/typescript-go/issues/4587#issuecomment-5047689267)_

According to @DanielRosenwasser, this isn't actually intentional and just kinda fell-out from the unified config handling we setup to handle falling back from the `js/ts` -> `typescript` -> `javascript` config namespaces.