feat: adds email as fallback for name in member details

lib/mv_web/live/user_live/index.html.heex

@@ -51,7 +51,7 @@
     </:col>
     <:col :let={user} label={gettext("Linked Member")}>
       <%= if user.member do %>
-        {user.member.first_name} {user.member.last_name}
+        {MvWeb.MemberLive.Index.display_name(user.member)}
       <% else %>
         <span class="text-base-content/50">{gettext("No member linked")}</span>
       <% end %>