Update random ID method to use str_random and not random_bytes

The use of random_bytes in combination with bin2hex was producing a lot of duplicate keys when tested in batches of 10k (anywhere from 2 to 6). The use of str_random yielded no duplicates even at scales of 100k keys that were 8 characters.

tests/Unit/Services/Nodes/NodeCreationServiceTest.php

@@ -61,12 +61,12 @@ class NodeCreationServiceTest extends TestCase
      */
     public function testNodeIsCreatedAndDaemonSecretIsGenerated()
     {
-        $this->getFunctionMock('\\Pterodactyl\\Services\\Nodes', 'bin2hex')
-            ->expects($this->once())->willReturn('hexResult');
+        $this->getFunctionMock('\\Pterodactyl\\Services\\Nodes', 'str_random')
+            ->expects($this->once())->willReturn('random_string');
 
         $this->repository->shouldReceive('create')->with([
             'name' => 'NodeName',
-            'daemonSecret' => 'hexResult',
+            'daemonSecret' => 'random_string',
         ])->once()->andReturnNull();
 
         $this->assertNull($this->service->handle(['name' => 'NodeName']));