Builder fiddle within Mitosis fiddle breaks if logged-in

to reproduce:
- go to https://mitosis.builder.io/ while logged out: bottom fiddle shows component
- now, go to builder.io and login
- go back to https://mitosis.builder.io as a logged-in Builder user: bottom fiddle is now blank

Reproduce the issue at https://mitosis.builder.io/ while logged out and then as a logged-in Builder user, comparing the bottom fiddle. Trace the fiddle integration from that page; done means the component renders correctly in both authentication states.

Written by the indexing model from the issue text.