feat: update voucher purchase urls to match established patterns

tests/Controller/Voucher/Step3ControllerTest.php

@@ -140,7 +140,7 @@ class Step3ControllerTest extends TestCase
      */
     public function testASecondSubmitCannotBuyTwice(): void
     {
-        $request = Request::create('/gutschein/uebersicht', 'POST');
+        $request = Request::create('/vouchers/create/confirmation', 'POST');
         $request->setSession(new Session(new MockArraySessionStorage()));
 
         $voucherClient = $this->createMock(VoucherClient::class);
@@ -172,7 +172,7 @@ class Step3ControllerTest extends TestCase
 
     private function createRequest(string $method, VoucherPurchaseDto $dto): Request
     {
-        $request = Request::create('/gutschein/uebersicht', $method);
+        $request = Request::create('/vouchers/create/confirmation', $method);
         $request->setSession(new Session(new MockArraySessionStorage()));
         $this->sessionManager->save($request, $dto);