fix: update stripe projects add command to new syntax (#45471)

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

Update CLI command

## What is the current behavior?

N/A

## What is the new behavior?

Latest CLI command

## Additional context

N/A


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Documentation**
* Updated terminal setup instructions for Stripe project integration to
reflect current configuration parameters.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Co-authored-by: Ana <ana1337x@users.noreply.github.com>

apps/www/_go/events/stripe-sessions-2026/contest.tsx

@@ -46,7 +46,7 @@ const page: GoPageInput = {
             <pre className="bg-surface-200 rounded-md p-4 text-sm text-foreground-light overflow-x-auto">
               <code>{`stripe plugin install projects
 stripe projects init my-app
-stripe projects add supabase/supabase:free
+stripe projects add supabase/project
 stripe projects env --sync`}</code>
             </pre>
             <p className="text-foreground-lighter text-sm">