Move SSBC to beta

Created by: eseliger

HERE WE GO; YOU SAY SERVER WE SAY SIDE. YOU SAY BATCH WE SAY CHANGES. 🎤 ⬇️

Long-anticipated moment, here we go :)

What does this mean?

It means that we, by default, show the editor UI to all users. All src-cli workflows users are used to are still working just as before. In addition, they will be able to from the editor download the spec file for src-cli execution. They will also be nudged to give server-side execution a try. We want to tighten the feedback loop and ship incrementally from here, so every release should be packed with lots of small-step improvements from now on, eventually leading to a GA of the feature.

DON'T MERGE UNTIL WE SORTED OUT SOME MORE THINGS, BUT PLEASE APPROVE AND CELEBRATE

Test plan

Verified all UIs still show when the flag is enabled.