refactor(modules): drop redundant hidden_field_tag in preferences view

DS::Toggle already renders its own `hidden_field_tag name, unchecked_value,
id: nil` (app/components/DS/toggle.html.erb:2), so the explicit one I
added was duplicating the unchecked-value field — and was the root cause
of the ID collision the prior commit worked around with `id: nil`.

Removing the redundant line is the correct fix; live-tested via
Playwright (toggle persists, off-state arrives as "0" through the
DS-provided hidden).

app/views/settings/preferences/show.html.erb

@@ -246,7 +246,6 @@
             <h5 class="text-primary"><%= t("modules.#{module_name}.title") %></h5>
             <p class="text-secondary"><%= t("modules.#{module_name}.description") %></p>
           </div>
-          <%= hidden_field_tag "family[modules][#{module_name}]", "0", id: nil %>
           <%= render DS::Toggle.new(
                 id: "family_modules_#{module_name}",
                 name: "family[modules][#{module_name}]",