Chore: Remove duplicate function
Bugfix: Prompt throws error when no local tunnels are installed
Fix a problem where the local tunnel indicator on the prompt throws an error if
no local tunnels are installed.

This has the added benefit of making the `__which_local_tunnel_is_running` check
much more generic and prepares us for integrating with ngrok.

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Change-Id:     Ib840226c61c67b9c836c73163ffbdca5e2250b5b
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>