feat(donation): Use new endpoint for creating anon donations

src/components/donations/AddDonationModal.svelte

@@ -76,7 +76,7 @@
 				let postdata = {
 					amount: amount_cent,
 				};
-				DonationService.donationControllerPostFixed(postdata)
+				DonationService.donationControllerPostAnonymous(postdata)
 					.then((result) => {
 						amount_input = 0;
 						modal_open = false;