fix(savings_goals/empty_state): pass return_to so user lands back on /savings_goals after adding an account

The "Add an account" CTA on the no-depository-accounts empty state now
appends ?return_to=/savings_goals. StoreLocation already stashes the
param into session via the global before_action; the consuming side
(subtype #create actions) honouring it is tracked at
we-promise/sure#1766.

app/views/savings_goals/_empty_state.html.erb

@@ -21,7 +21,7 @@
       <%= render DS::Link.new(
         text: t("savings_goals.empty_state.add_account"),
         variant: "primary",
-        href: new_account_path,
+        href: new_account_path(return_to: savings_goals_path),
         icon: "plus"
       ) %>
     <% end %>