Don't allow to modify questions for started polls

Adding, modifiying, and/or deleting questions for an already started
poll is far away from being democratic and can lead to unwanted side
effects like missing votes in the results or stats.

So, from now on, only modifiying questions will be possible only if
the poll has not started yet.

spec/components/admin/poll/questions/table_actions_component_spec.rb

@@ -0,0 +1,25 @@
+require "rails_helper"
+
+describe Admin::Poll::Questions::TableActionsComponent, controller: Admin::BaseController do
+  before { sign_in(create(:administrator).user) }
+
+  it "displays the edit and destroy actions when the poll has not started" do
+    question = create(:poll_question, poll: create(:poll, :future))
+
+    render_inline Admin::Poll::Questions::TableActionsComponent.new(question)
+
+    expect(page).to have_link "Edit answers"
+    expect(page).to have_link "Edit"
+    expect(page).to have_button "Delete"
+  end
+
+  it "does not display the edit and destroy actions when the poll has started" do
+    question = create(:poll_question, poll: create(:poll))
+
+    render_inline Admin::Poll::Questions::TableActionsComponent.new(question)
+
+    expect(page).to have_link "Edit answers"
+    expect(page).not_to have_link "Edit"
+    expect(page).not_to have_button "Delete"
+  end
+end