Build: Use next branch for sandbox and repro commands

[yannbf]

Closes #

What I did

As part of the 7.0.0 next to main merge process, we changed the sandbox generation to refer to themain branch, but we forgot to bring it back to next! 😮‍💨

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• If this PR should be tested against many or all sandboxes,
  make sure to add the ci:merged or ci:daily GH label to it.
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "documentation", "maintenance", "dependencies", "other"]

[shilman]

do we need to run it differently on main/next branches?

[yannbf]

do we need to run it differently on main/next branches?

I'm not sure if I got the question right, but:

If we run the sandbox task in main branch of the monorepo, we should run sandbox --branch=main so we download the before-storybook directory of the main branch of the sandboxes repo repo, which was generated by sandbox-templates.ts of the main branch of the monorepo.

If we run the sandbox task in next branch of the monorepo, we should run sandbox --branch=next so we download the before-storybook directory of the next branch of the sandboxes repo repo, which was generated by sandbox-templates.ts of the next branch of the monorepo.

[shilman]

@yannbf if we run it differently on the main/next branches why is changing the default in this PR important? or an alternative question is why did we change it in the first place?

[yannbf]

@yannbf if we run it differently on the main/next branches why is changing the default in this PR important? or an alternative question is why did we change it in the first place?

I was saying what should happen, not what happens. Currently, both main and next branches are running sandbox --branch=main.

As for the alternative question, I explained it in the description of this PR:
As part of the 7.0.0 next to main merge process, we changed the sandbox generation to refer to the main branch, but we forgot to bring it back to next! 😮‍💨