ci: skip website report deploy for fork PRs (#13344)

## Summary

Skip the website e2e report/deploy step for fork PRs, which lack the
deploy secrets and otherwise fail the job.

## Changes

- **What**: Guard the report/deploy step's `if:` in
`ci-website-e2e.yaml` so it runs only when the event is not a fork pull
request.
- **Breaking**: none. CI-config only.

## Review Focus

CI-config only — no test or coverage change. Confirms fork PRs no longer
fail on the deploy step.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> CI workflow condition only; no application or test logic changes.
> 
> **Overview**
> **Website E2E CI** no longer runs the **Deploy report to Cloudflare**
step on pull requests from forks.
> 
> The step’s `if:` still requires `always()` and `!cancelled()`, and now
also requires either a non–pull-request event or a PR whose head repo is
**not** a fork. Playwright tests and artifact upload are unchanged; only
the wrangler deploy (which needs `CLOUDFLARE_*` secrets) is skipped for
fork PRs so those runs don’t fail when secrets aren’t available.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
02a4ab0. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Co-authored-by: huang47 <157390+huang47@users.noreply.github.com>

Author: huang47