fix: omit projectId from webhook update API schema

The ZWebhookUpdateSchema derived from ZWebhook via .omit() did not exclude
projectId, making it a required field in the update payload. This caused
the webhook update E2E test to fail since it doesn't send projectId.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/modules/api/v2/management/webhooks/[webhookId]/types/webhooks.ts

@@ -17,6 +17,7 @@ export const ZWebhookUpdateSchema = ZWebhook.omit({
   createdAt: true,
   updatedAt: true,
   environmentId: true,
+  projectId: true,
   secret: true,
 }).meta({
   id: "webhookUpdate",