CASH-132: set up manual test of save donation to session order

src/layouts/confirmation/confirmation.vue

@@ -67,6 +67,8 @@
                             <div class="mt-3">
                                 <donationBlock cmsWidgetName="DonationWidget" />
                             </div>
+                            
+                            <button type="button" @click="addDonation(3)">Add Donation of $3</button>
 
                             <hr class="mb-5" />
 
@@ -494,6 +496,13 @@ export default {
         forwardButtonAction() {
             window.location.assign(location.protocol + "//" + location.host);
         },
+        addDonation(amount) {
+            baseMixin.methods.dispatchStoreAction(
+                storeActions.ADD_DONATION_TO_SUBMITTED_ORDER,
+                amount,
+                false
+            );
+        }
     },
     components: {
         funnelHeader,