Move tests related with attached documents from documentable shared specs to nested documentable file

Note that we moved some system tests to component tests, since they don't involve user interaction and can
be fully covered at the component level.

spec/system/nested_documentable_spec.rb

@@ -287,4 +287,35 @@ describe "Nested documentable" do
       end
     end
   end
+
+  context "Show path" do
+    let(:factory) { (factories - [:dashboard_action]).sample }
+    let(:path) { polymorphic_path(documentable) }
+
+    scenario "Documents list should not be available when allow attached documents setting is disabled" do
+      Setting["feature.allow_attached_documents"] = false
+      create(:document, documentable: documentable)
+      visit path
+
+      expect(page).not_to have_css("#documents")
+    end
+
+    context "Destroy" do
+      scenario "Should show success notice after successful document upload" do
+        create(:document, documentable: documentable)
+        documentable.update!(author: user)
+        login_as(user)
+        visit path
+
+        accept_confirm { click_button "Delete document" }
+
+        expect(page).to have_content "Document was deleted successfully."
+        expect(page).not_to have_content "Documents (0)"
+
+        within "##{ActionView::RecordIdentifier.dom_id(documentable)}" do
+          expect(page).to have_css "h1", text: documentable.title
+        end
+      end
+    end
+  end
 end