fatalErrorHandler returns 500 only on fatal errors

fatalogErrorHandler should return 500 only on fatal errors - otherwise, even a simple deprecation warning on the page triggers internal server error, which is invalid.

pub/health_check.php

@@ -70,7 +70,7 @@
 function fatalErrorHandler()
 {
     $error = error_get_last();
-    if ($error !== null) {
+    if ($error !== null && $error['type'] === E_ERROR) {
         http_response_code(500);
     }
 }