Do not show confirm message if user can vote in all headings

spec/system/budgets/votes_spec.rb

@@ -198,6 +198,16 @@ describe "Votes" do
 
         expect(page.driver.send(:find_modal).text).to match "You can only support investments in 2 districts."
       end
+
+      scenario "Do not show confirm message if user can vote in all headings" do
+        group.update!(max_votable_headings: group.headings.count)
+
+        visit budget_investments_path(budget, heading_id: new_york.id)
+        click_button "Support"
+
+        expect(page).to have_content "1 support"
+        expect(page).to have_content "You have already supported this investment project. Share it!"
+      end
     end
   end