Fix default exception class selection.

Closes #64.

Author: ADmad

src/Auth/JwtAuthenticate.php

@@ -98,7 +98,7 @@ public function __construct(ComponentRegistry $registry, $config)
             'key' => null,
         ];
 
-        if (!class_exists(UnauthorizedException::class, false)) {
+        if (!class_exists(UnauthorizedException::class)) {
             $defaultConfig['unauthenticatedException'] = 'Cake\Network\Exception\UnauthorizedException';
         }
 

tests/TestCase/Auth/JwtAuthenticateTest.php

@@ -260,6 +260,7 @@ public function testUnauthenticated()
     {
         $this->Registry->Auth->setConfig('authError', 'Auth error');
 
+        $exceptionClass = UnauthorizedException::class;
         if (!class_exists(UnauthorizedException::class)) {
             $exceptionClass = 'Cake\Network\Exception\UnauthorizedException';
         }