Using all of TypeBot's features in the preview.

[dllspp]

Describe the bug
I noticed that when creating a /preview session in Typebot, we can use the infrastructure freely without needing to use the free plan.

To reproduce
Steps to reproduce the behavior:

1. When generating https://typebot.io/api/v1/typebots//preview/startChat
2. Then we can use https://typebot.io/api/v1/sessions//continueChat for free.

Expected behavior
Since it's just a preview, shouldn't there be a usage limitation?