Fix investment support in management section

When supporting an investment in the management section through the
investment view, we were accessing an action in the public investments
controller. This meant the manager was the one supporting the investment
(as they'd be the `current_user` in this controller) and not the managed
user.

In the case of groups with many headings, voting the first time requires
a confirmation and then a regular (non-AJAX) request takes place. In
this case, users were redirected to the public area instead of remaining
in the management area.

Using the proper URL to vote solves the problem.

Note there was a comment about one of these tests failing in Travis.
Most probably the test failed because there was no expectation after
clicking the link with the investment title, so the "Support" button
(which is also present in the index page) was clicked before the
investment view was loaded.

app/views/budgets/investments/_investment_show.html.erb

@@ -35,7 +35,7 @@
                 <%= render "/budgets/investments/votes",
                   investment: investment,
                   investment_votes: investment_votes,
-                  vote_url: vote_budget_investment_path(investment.budget, investment, value: "yes") %>
+                  vote_url: namespaced_budget_investment_vote_path(investment, value: "yes") %>
               </div>
             </div>
           <% elsif investment.should_show_vote_count? %>

spec/system/management/budget_investments_spec.rb

@@ -284,9 +284,9 @@ describe "Budget Investments" do
       end
     end
 
-    # This test passes ok locally but fails on the last two lines in Travis
-    xscenario "Supporting budget investments on behalf of someone in show view" do
+    scenario "Supporting budget investments on behalf of someone in show view" do
       budget_investment = create(:budget_investment, budget: budget)
+      manager.user.update!(level_two_verified_at: Time.current)
 
       login_managed_user(user)
       login_as_manager(manager)
@@ -300,9 +300,36 @@ describe "Budget Investments" do
         click_link budget_investment.title
       end
 
+      expect(page).to have_css "h1", exact_text: budget_investment.title
+
       find(".js-in-favor a").click
+
       expect(page).to have_content "1 support"
-      expect(page).to have_content "You have already supported this. Share it!"
+      expect(page).to have_content "You have already supported this investment project. Share it!"
+
+      refresh
+
+      expect(page).to have_content "1 support"
+      expect(page).to have_content "You have already supported this investment project. Share it!"
+    end
+
+    scenario "Support investments on behalf of someone else when there are more headings" do
+      create(:budget_investment, heading: heading, title: "Default heading investment")
+      create(:budget_investment, heading: create(:budget_heading, group: group))
+
+      login_managed_user(user)
+      login_as_manager(manager)
+
+      visit management_budget_investments_path(budget)
+      click_link "Default heading investment"
+
+      expect(page).to have_css "h1", exact_text: "Default heading investment"
+
+      accept_confirm { find(".js-in-favor a").click }
+
+      expect(page).to have_content "1 support"
+      expect(page).to have_content "You have already supported this investment project. Share it!"
+      expect(page).to have_content "CONSUL\nMANAGEMENT"
     end
 
     scenario "Should not allow unverified users to vote proposals" do