rbx_cookie does not consider WSL as a windows operating system

[sasial-dev]

Describe the bug
If the user is running inside WSL it should still grab the cookie from wincred for the running studio instance.

Expected behavior
I was trying to debug an issue as to why another programmer couldn't get their cookie, until I realised they're running inside WSL. When rbx_cookie is compiled for linux it will return None, which is not helpful inside WSL. It should return the cookie for the running studio instnace.

To Reproduce

1. Open an instance of roblox studio and log in
2. Run rbx_cookie::get() from WSL