ENGCOM-2931: [Forwardport] Fix proxy generation return type #17768

 - Merge Pull Request #17768 from nmalevanec/magento2:2.3-develop-PR-port-17552
 - Merged commits:
   1. 691d187

Author: magento-engcom-team

lib/internal/Magento/Framework/ObjectManager/Test/Unit/Code/Generator/_files/Sample.php

@@ -16,6 +16,11 @@ class Sample
      */
     protected $messages = [];
 
+    /**
+     * @var array
+     */
+    private $config = [];
+
     /**
      * @param array $messages
      */
@@ -31,4 +36,20 @@ public function getMessages()
     {
         return $this->messages;
     }
+
+    /**
+     * @param array $config
+     */
+    public function setConfig(array $config)
+    {
+        $this->config = $config;
+    }
+
+    /**
+     * @return array
+     */
+    public function getConfig(): array
+    {
+        return $this->config;
+    }
 }

lib/internal/Magento/Framework/ObjectManager/Test/Unit/Code/Generator/_files/SampleProxy.txt

@@ -101,4 +101,20 @@ class Sample_Proxy extends Sample implements \Magento\Framework\ObjectManager\No
     {
         return $this->_getSubject()->getMessages();
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function setConfig(array $config)
+    {
+        return $this->_getSubject()->setConfig($config);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getConfig() : array
+    {
+        return $this->_getSubject()->getConfig();
+    }
 }