Don't crash if email address has sub-address with special characters

Emails with [sub-addressing](https://en.wikipedia.org/wiki/Email_address#Sub-addressing) should not
cause the donations flow to crash. It currently does because the vipps redirect URL validation fails
because of the special characters involved, namely "+", e.g. "olav+subscriptions@example.com".

lib/vipps/vipps.ts

@@ -3,6 +3,7 @@ import "jsr:@std/dotenv/load";
 import { encodeHex } from "jsr:@std/encoding/hex";
 import { getHostUrl } from "../utils.ts";
 import { STATUS_CODE } from "$fresh/server.ts";
+import { base } from "npm:@faker-js/faker";
 
 const config = {
   clientId: Deno.env.get("VIPPS_CLIENT_ID"),
@@ -50,6 +51,12 @@ const getAccessToken = async function () {
 export const createAgreement = async function (email: string) {
   const token = await getAccessToken();
   const amount = 5000; // 50 NOK
+
+  // in case of special characters, like sub-addresses added
+  // with +, e.g. "name+subscriptions@domain.com"
+  const urlEncodedEmail = encodeURIComponent(email);
+  const redirectUrl = `${getHostUrl()}/donations-success?urlEncodedEmail=${urlEncodedEmail}`;
+  console.log(redirectUrl, "HER ER DET");
   const response = await fetch(`${config.baseUrl}/recurring/v3/agreements/`, {
     method: "POST",
     // @ts-ignore
@@ -74,7 +81,7 @@ export const createAgreement = async function (email: string) {
         currency: "NOK",
       },
       // email is used to identify the user in the success page
-      merchantRedirectUrl: `${getHostUrl()}/donations-success?email=${email}`,
+      merchantRedirectUrl: redirectUrl,
       merchantAgreementUrl: `${getHostUrl()}`,
       productName: "Månedlig støtte til NRSS",
     }),

routes/donations-success.tsx

@@ -5,7 +5,9 @@ import { validateEmail } from "../lib/utils.ts";
 export const handler: Handlers = {
   async GET(request, ctx) {
     const url = new URL(request.url);
-    const email = url.searchParams.get("email");
+    const urlEncodedEmail = url.searchParams.get("urlEncodedEmail");
+    const email = urlEncodedEmail ? decodeURIComponent(urlEncodedEmail) : null;
+
     if (!email) {
       console.error("Missing email in query params", request.url);
       return Response.redirect("/donations-error");
@@ -34,9 +36,7 @@ export const handler: Handlers = {
 export default function () {
   return (
     <div className="my-16 text-center flex flex-col items-center  min-h-screen ">
-      <h1 className="text-6xl mb-8">
-        🙏🌟😊💖
-      </h1>
+      <h1 className="text-6xl mb-8">🙏🌟😊💖</h1>
       <p className="text-4xl mb-4">
         Tusen takk! Jeg er veldig takknemlig for all støtte.
       </p>