Remove debug code which makes the filter abort

Problem/Motivation

Apparently the code contains debug code. The filter does not actually work, it just aborts.

Steps to reproduce

Install the module and create a Twig field / view / ..., where you use the decode_json filter (e.g. '{{ "[1,2,3]"|decode_json }}').

Proposed resolution

Remove the line 17 from src/JsonToArray.php:

var_dump($context);die();