Add trial chambers in structures.yml

[pigeonov]

Is your feature request related to a problem?

Yes, because trial chambers generated by seed doesn't working properly

Describe the solution you'd like.

Add trial chambers in structures, and make trial spawners work

Describe alternatives you've considered.

...

Agreements

• I have searched for and ensured there isn't already an open issue regarding this.
• I have ensured the feature I'm requesting isn't already in the latest supported BentoBox build or Addons.

Other

No response