Fix for custom front end , playground.tsx

[btebbutt]

In the backend example provided in the cookbook is used, the chat UI works well , however as soon as other libraries that use their own call backs are inserted into the backend , every time the LLM responds , there is a blank empty text box created . E.g.

this is fixed by adding a small condition in the render message function within playground.tsx :

[ModEnter]

Hello, since the playground has been removed from chainlit, I'm closing this issue. Feel free to ask any code-related question on the Chainlit's discord, to interact directly with the chainlit community 😉