Parse text/HTML as JSON in WSO2 Micro integrator

Question

When I use EI, I add the following to enable text/HTML to be parsed as JSON under axis2.xml:

    <messageFormatter contentType="text/html" 
class="org.apache.synapse.commons.json.JsonStreamFormatter"/>

   <messageBuilder contentType="text/html" 
  class="org.apache.synapse.commons.json.JsonStreamBuilder"/>

However this did not work on the micro integrator latest version. I tried to add it to the deployment.toml under [[custom_message_builders]] and [[custom_message_formatters]], but it did not work as well.

Under https://ei.docs.wso2.com/en/latest/micro-integrator/setup/message_builders_formatters/message-builders-and-formatters/ they explained that we can add the text/html as custom and write our own class, but it was supported on EI before, why won't it work under the latest version?