Remove deprecated Address fields from json representation

When Spree::Config.use_combined_first_and_last_name_in_address
preference is set to true, no Address representation should contain any
reference to deprecated legacy name attributes.

core/app/models/spree/address.rb

@@ -191,6 +191,16 @@ def name=(value)
       write_attribute(:lastname, name_from_value.last_name)
     end
 
+    def as_json(options = {})
+      if Spree::Config.use_combined_first_and_last_name_in_address
+        super(options.merge(except: LEGACY_NAME_ATTRS)).tap do |hash|
+          hash['name'] = name
+        end
+      else
+        super
+      end
+    end
+
     private
 
     def validate_name

core/spec/models/spree/address_spec.rb

@@ -379,6 +379,12 @@
 
       expect(address.name).to eq('')
     end
+
+    it 'is included in json representation' do
+      address = Spree::Address.new(name: 'Jane Von Doe')
+
+      expect(address.as_json).to include('name' => 'Jane Von Doe')
+    end
   end
 
   context '#state_text' do
@@ -409,6 +415,10 @@
   context 'deprecations' do
     let(:address) { described_class.new }
 
+    specify 'json representation does not contain deprecated fields' do
+      expect(address.as_json).not_to include('firstname', 'lastname')
+    end
+
     specify 'firstname is deprecated' do
       expect(Spree::Deprecation).to receive(:warn).with(/firstname/, any_args)