neofetch: Don't hang on FreeBSD if pkg is not yet bootstrapped

[jrtc27]

If not yet bootstrapped, pkg will print out:

The package management tool is not yet installed on your system.
Do you want to fetch and install it now? [y/N]: 

and wait for input if stdin is a tty. Use </dev/null to squash this.

[hykilpikonna]

Thank you for your contribution!

This PR is merged into hyfetch since this repo (dylanaraps/neofetch) seems no longer maintained.

HyFetch is a fork of neofetch with LGBTQ pride flags, but the repo also maintains an updated version of the original neofetch, addressing many pull requests that are not merged in the original repo.

Read the "Running Updated Original Neofetch" section for more info!