Change some methods to public to be accessible for plugins

[sanderjongsma]

There are a lot of private functions and in my opinion some of them should be public to make them accessible for plugins in Magento. In this PR case I changed just two methods because I need them to be accessible to add some changes on client level and I think they don't need to be private.

[sanderjongsma]

Other possibilities are:

• Add a complete new AddressHandler to the constructor in di.xml but this means more maintenance with updates.
• Use a patch to change the methods to public.
• The addAddressData is public, so I can use that one to do some changes

Just letting you know how private functions can limit your options.