Make sure action names are in sync with helper definition

This prevents names getting out of sync.

ee/app/helpers/ee/system_note_helper.rb

@@ -19,9 +19,9 @@ module EE
       'weight' => 'weight',
       'relate_epic' => 'epic',
       'unrelate_epic' => 'epic',
-      'design_added' => 'doc-image',
-      'design_modified' => 'doc-image',
-      'design_removed' => 'doc-image'
+      'designs_added' => 'doc-image',
+      'designs_modified' => 'doc-image',
+      'designs_removed' => 'doc-image'
     }.freeze
 
     override :system_note_icon_name

ee/spec/services/system_note_service_spec.rb

@@ -99,6 +99,32 @@ describe SystemNoteService do
       end
     end
 
+    describe 'icons' do
+      where(:action) do
+        [
+          [:creation],
+          [:modification],
+          [:deletion]
+        ]
+      end
+
+      with_them do
+        before do
+          version.actions.update_all(event: action)
+        end
+
+        subject(:metadata) do
+          described_class.design_version_added(version)
+            .first.system_note_metadata
+        end
+
+        it 'has a valid action' do
+          expect(EE::SystemNoteHelper::EE_ICON_NAMES_BY_ACTION)
+            .to include(metadata.action)
+        end
+      end
+    end
+
     context 'it succeeds' do
       where(:action, :icon, :human_description) do
         [