Bug report: Error saving default columns on events in data management

Bug Description

Please describe.

When editing default columns for matching events on an event definition in data management, if you check the box for Save as default columns for this event type , error toast pops showing "Failed to save columns to event definition".

The console shows a 402 payment required error, with message detail "This feature is part of the premium PostHog offering. To use it, subscribe to PostHog Cloud with a generous free tier."

The customer reporting the bug is on the YC plan, and the Save as default columns for this event type does work for them on the Activity page.

How to reproduce

Example event definition in data management

1. Go to Data management --> Event definitions and click on an event
2. Scroll down to the Matching events section o' the page
3. Click the Configure columns button
4. Add a property (e.g., one which exists on the event)
5. Check the box for Save as default columns for this event type
6. Click the Save button
7. See the error message

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/37500 (moved to PostHog: https://us.posthog.com/project/2/support/tickets/38628)

Debug info

Debug info
Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/01992ba9-9deb-7f5f-ac36-783abd46b8fd?t=1271
Admin: http://go/adminOrgUS/019819c9-3651-0000-d12e-e576fac3858e (project ID 195693)

Reproduce the failure from the event definition's Matching events section using Configure columns, then compare it with the working Activity page flow. Trace the save request and its entitlement handling for the YC plan; done means default columns save successfully without the 402 error and existing behavior remains intact.