Respect the user addressbook label
Respect the user addressbook label

This PR allows the user to have any label they like (iOS allows for
custom labels).

It also fixes a bug here if the user’s label was capital letters, this
check did not correctly match the label

joshuapinter/react-native-unified-contacts,joshuapinter/react-native-unified-contacts,joshuapinter/react-native-unified-contacts,joshuapinter/react-native-unified-contacts