ENGCOM-4681: unregister phar only when appropriate #22171

 - Merge Pull Request #22171 from adaudenthun/magento2:2.3-develop
 - Merged commits:
   1. 191fc7c

Author: magento-engcom-team

app/bootstrap.php

@@ -8,7 +8,9 @@
  * Environment initialization
  */
 error_reporting(E_ALL);
-stream_wrapper_unregister('phar');
+if (in_array('phar', \stream_get_wrappers())) {
+    stream_wrapper_unregister('phar');
+}
 #ini_set('display_errors', 1);
 
 /* PHP version validation */