[DependencyInjection] Fix loading all env vars from secrets when only a subset is needed

Author: nicolas-grekas

LazyString.php

@@ -39,7 +39,7 @@ public static function fromCallable(callable|array $callback, mixed ...$argument
                     $callback[1] ??= '__invoke';
                 }
                 $value = $callback(...$arguments);
-                $callback = self::getPrettyName($callback);
+                $callback = !\is_scalar($value) && !$value instanceof \Stringable ? self::getPrettyName($callback) : 'callable';
                 $arguments = null;
             }