Fix CLI command for non-local API configuration

[DL6ER]

What does this implement/fix?

In the corner-case of a user explicitly having configured Pi-hole to NOT listen on lo (because there may be another webserver, etc.), the pihole CLI command may be unable to communicate with the API due to the hard-coded path "localhost". Change this to use the special "pi.hole" host name where interface-dependent replying is already implemented

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Related issue or feature (if applicable): Fixes #2192

Pull request in docs with documentation (if applicable): N/A

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