Bug: nothing happens when i press upgrade

Bug Description

Please describe.
If this affects the front-end, screenshots would be of great help.

I have 6 projects already but when i press upgrade (to try add some more projects) nothing seems to happen.

https://github.com/user-attachments/assets/886f7417-142f-49b9-81d7-dbb7807e88fe

If you are on PostHog Cloud it would be really valuable if you can share any links where the problem occurs. This speeds up our ability to troubleshoot tremendously.

How to reproduce

1. be on free tier
2. make 6 projects
3. try to jut add a new one on the fly from one of the 6
4. press upgrade

Additional context

I checked the console but dont see any errors in there

Debug info

- [X] PostHog Cloud, Debug information: [please copy/paste from https://us.posthog.com/settings/project-details#variables or https://eu.posthog.com/settings/project-details#variables]
- [ ] PostHog Hobby self-hosted with `docker compose`, version/commit: [please provide]
- [ ] PostHog self-hosted with Kubernetes (deprecated, see [`Sunsetting Kubernetes support`](https://posthog.com/blog/sunsetting-helm-support-posthog)), version/commit: [please provide]

Start by reproducing the issue on PostHog Cloud using the listed free-tier steps: create six projects and press Upgrade while adding another. Check the attached screenshot and browser console, then trace the upgrade flow until you can identify why the expected upgrade action does not occur; done means the button reliably starts the upgrade flow.