fix user update

src/Api/Controller/APIAccountsController.php

@@ -34,7 +34,6 @@ class APIAccountsController {
      */
     public function listUsers(array $request): HttpResponse {
         return APIControl::runCheckedFrom($request, [
-
             'start' => [DefaultValidators::isUnsignedInteger()],
             'n' => [DefaultValidators::isIntInRange(0, 250)],
             'search' => [DefaultValidators::lenBetween(0, 256)],
@@ -97,8 +96,9 @@ class APIAccountsController {
             "username" => [DefaultValidators::name()],
             "isAdmin" => [DefaultValidators::bool()],
         ], function (HttpRequest $req) use ($id) {
-            $mailAccount = $this->accounts->getAccount($id);
-            if ($mailAccount->getUser()->getId() != $id) {
+            $mailAccount = $this->accounts->getAccountFromMail($req["email"]);
+
+            if ($mailAccount != null && $mailAccount->getUser()->getId() != $id) {
                 return new JsonHttpResponse([new ValidationFail("email exists", "The provided mail address already exists for another account.")], HttpCodes::FORBIDDEN);
             }