Convert ApiControllerBase::createJsonResponseFromViolationSets() to custom exception

wim leers → credited larowlan → .

📌 Throw exceptions instead of returning tuples for validation errors Active is in — this needs a rebase. Looking forward to this landing! :)

longwave → changed the visibility of the branch 3497695-convert-apicontrollerbasecreatejsonresponsefromviolationsets-to to hidden.

wim leers → closed merge request !511

Looking great! for:

• Requesting to restore a DX improvement that 📌 [PP-1] Send page data to Drupal for storage in auto-save store Postponed: needs info landed yesterday that this MR is reverting.
• Deleting one now pointless file.

@longwave: could you push this one across the finish line? 🙏 ✨ Provide a way to create a new page Active mistakenly was extending the ApiControllerBase class, and this MR is removing it, which would've prevented that understandable confusion!