feat: adds email as fallback for name in member details

lib/mv_web/live/custom_field_value_live/form.ex

@@ -289,6 +289,6 @@ defmodule MvWeb.CustomFieldValueLive.Form do
   end
 
   defp member_options(members) do
-    Enum.map(members, &{"#{&1.first_name} #{&1.last_name}", &1.id})
+    Enum.map(members, &{MvWeb.MemberLive.Index.display_name(&1), &1.id})
   end
 end