FEATURE: add site setting to include user associated account ids. (#18375)

By default, we won't include associated account ids in current user serializer. If the new hidden site setting `include_associated_account_ids` is enabled then we will add it in the serializer.

app/serializers/current_user_serializer.rb

@@ -58,6 +58,7 @@ class CurrentUserSerializer < BasicUserSerializer
              :can_create_group,
              :link_posting_access,
              :external_id,
+             :associated_account_ids,
              :top_category_ids,
              :hide_profile_and_presence,
              :groups,
@@ -293,6 +294,20 @@ class CurrentUserSerializer < BasicUserSerializer
     SiteSetting.enable_discourse_connect
   end
 
+  def associated_account_ids
+    values = {}
+
+    object.user_associated_accounts.map do |user_associated_account|
+      values[user_associated_account.provider_name] = user_associated_account.provider_uid
+    end
+
+    values
+  end
+
+  def include_associated_account_ids?
+    SiteSetting.include_associated_account_ids
+  end
+
   def second_factor_enabled
     object.totp_enabled? || object.security_keys_enabled?
   end