Add missing expectations after consecutive visits

This way we're 100% sure we won't have simultaneous requests since the
test will wait for one request to finish before continuing.

In the debates spec, we're also making sure the expectations between the
two consecutive visits are different.

spec/system/debates_spec.rb

@@ -664,10 +664,11 @@ describe "Debates" do
     user.erase
 
     visit debates_path
-    expect(page).to have_content("User deleted")
+    expect(page).to have_content "User deleted"
 
     visit debate_path(debate)
-    expect(page).to have_content("User deleted")
+    expect(page).to have_css "h1", exact_text: debate.title
+    expect(page).to have_content "User deleted"
   end
 
   context "Suggesting debates" do

spec/system/sessions_spec.rb

@@ -39,7 +39,13 @@ describe "Sessions" do
     user = create(:user, :level_two)
 
     visit debates_path
+
+    expect(page).to have_content "Help with debates"
+
     visit "/"
+
+    expect(page).to have_content "Most active proposals"
+
     click_link "Sign in"
     fill_in "user_login", with: user.email
     fill_in "user_password", with: user.password