hostip: (macOS) free returned memory of SCDynamicStoreCopyProxies

hostip: (macOS) free returned memory of SCDynamicStoreCopyProxies

From Apples documentation on SCDynamicStoreCopyProxies, "Return Value: A
dictionary of key-value pairs that represent the current internet proxy
settings, or NULL if no proxy settings have been defined or if an error
occurred. You must release the returned value."

Failure to release the returned value of SCDynamicStoreCopyProxies can
result in a memory leak.

Source: https://developer.apple.com/documentation/systemconfiguration/1517088-scdynamicstorecopyproxies

Closes #7265