stripslashes_deep() on input

```
if ( ! empty( $_POST ) ) {
	$payload = $_POST;
} elseif ( $stdin = file_get_contents( 'php://input' ) ) {
	$payload = $stdin;
} elseif ( ! empty( $_GET ) ) {
	$payload = $_GET;
} else {
	$payload = null;
}
```

Regression introduced in 8c3f8220ee5fdf455df3bec96c4775b2048ca60b