Change user settings to be stored in a more optimal way (#23630)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/lib/user_settings_serializer.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class UserSettingsSerializer
+  def self.load(value)
+    json = begin
+      if value.blank?
+        {}
+      else
+        Oj.load(value, symbol_keys: true)
+      end
+    end
+
+    UserSettings.new(json)
+  end
+
+  def self.dump(value)
+    Oj.dump(value.as_json)
+  end
+end