Posts sent via websockets aren't sanitized properly

Posts aren't sanitized the same way when sent via Websockets as they are when saved to the database.

const MM_INSTANCE_URL = process.env.MM_INSTANCE_URL;
const MM_AUTH_TOKEN = process.env.MM_AUTH_TOKEN;
const MM_USER_ID = process.env.MM_USER_ID;
const MM_CHANNEL_ID = process.env.MM_CHANNEL_ID; // the ID of the channel where we create the post

const MM_TARGET_ID = "96nffx8oztncuyyxq7nj7p8seh"; // …