Allow toggling elements with the keyboard

Using `<a>` tags with no `href` means these elements cannot be activated
by keyboard users, so we're replacing them with buttons.

In the future we probably want to add more consistency so all toggle
buttons use the same code. We might also add styles depending on the
`aria-expanded` property.

spec/system/dashboard/dashboard_spec.rb

@@ -41,10 +41,15 @@ describe "Proposal's dashboard" do
       expect(page).to have_content(goal.title)
       expect(page).not_to have_content(future_goal.title)
 
-      find(:css, "#see_complete_course_link").click
+      click_button "Check out the complete course"
 
       expect(page).to have_content(goal.title)
       expect(page).to have_content(future_goal.title)
+
+      click_button "Hide course"
+
+      expect(page).to have_content(goal.title)
+      expect(page).not_to have_content(future_goal.title)
     end
   end
 
@@ -69,7 +74,7 @@ describe "Proposal's dashboard" do
     expect(page).to have_content(action.description)
     expect(page).to have_content("This is a really very long description for a proposed")
     expect(page).to have_selector("#truncated_description_dashboard_action_#{action_long.id}")
-    expect(page).to have_selector("a", text: "Show description")
+    expect(page).to have_button("Show description")
   end
 
   scenario "Dashboard progress do not display from the fourth proposed actions", js: true do
@@ -420,9 +425,13 @@ describe "Proposal's dashboard" do
     action_5 = create(:dashboard_action, :proposed_action, :active)
 
     visit recommended_actions_proposal_dashboard_path(proposal.to_param)
-    find(:css, "#see_proposed_actions_link_pending").click
+    click_button "Check out recommended actions"
 
     expect(page).to have_content(action_5.title)
+
+    click_button "Hide recommended actions"
+
+    expect(page).not_to have_content(action_5.title)
   end
 
   scenario "On recommended actions section display four proposed actions", js: true do