Use webhook_email for push webhook user_email

What does this MR do and why?

The push webhook builder read the raw public_email column directly, unlike every other webhook payload builder in this family. This meant users without a public email got an empty string, and project bots (which never have one) got null, instead of the documented [REDACTED] placeholder. Use webhook_email to match the existing convention and the documented behavior.

References

#390308 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

Setup

1. Go to a project page.
2. Go to Settings > Webhooks.
3. Click Add new webhook.
4. Set the URL to https://example.com (or use a tool like webhook.site to inspect payloads).
5. Under Trigger, select Push events.
6. Click Add webhook.

Validate the fix

7. On the webhook list, click Test > Push events.
8. Ignore the delivery failure (the URL is not real).
9. Click Edit on the webhook, then open the Recent events tab.
10. Expand the latest event and inspect the request payload.

Expected behavior

• If the push author has a public email set: user_email shows that email address.
• If the push author has no public email: user_email shows [REDACTED] instead of an empty string or null.

To test the [REDACTED] case, use a user account with no public email set (User Settings > Profile > Public email left blank), or use a project bot token to trigger the push.

MR acceptance checklist

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