feat: add person 4 known question

app/models/form/sales/pages/person4_known.rb

@@ -0,0 +1,19 @@
+class Form::Sales::Pages::Person4Known < ::Form::Page
+  def initialize(id, hsh, subsection)
+    super
+    @id = "person_4_known"
+    @header_partial = "person_4_known_page"
+    @header = ""
+    @description = ""
+    @subsection = subsection
+    @depends_on = [
+      { "hholdcount" => 4 },
+    ]
+  end
+
+  def questions
+    @questions ||= [
+      Form::Sales::Questions::Person4Known.new(nil, nil, self),
+    ]
+  end
+end

app/models/form/sales/questions/person4_known.rb

@@ -0,0 +1,24 @@
+class Form::Sales::Questions::Person4Known < ::Form::Question
+  def initialize(id, hsh, page)
+    super
+    @id = "details_known_4"
+    @check_answer_label = "Details known for person 4"
+    @header = "Do you know the details for person 4?"
+    @type = "radio"
+    @answer_options = ANSWER_OPTIONS
+    @page = page
+    @hint_text = ""
+    @hidden_in_check_answers = {
+      "depends_on" => [
+        {
+          "details_known_4" => 1,
+        },
+      ],
+    }
+  end
+
+  ANSWER_OPTIONS = {
+    "1" => { "value" => "Yes" },
+    "2" => { "value" => "No" },
+  }.freeze
+end