fix: replaced first name, last name or email to display name (#1796)

* fix: replacing first, last name and email with display name

* fix: different endpoint for workspace & project member

* fix: falling back to email if display_name doesn't exist

apps/app/pages/api/track-event.ts

@@ -26,6 +26,7 @@ export default async function handler(req: NextApiRequest, res: NextApiResponse)
       email: user.email,
       first_name: user.first_name,
       last_name: user.last_name,
+      display_name: user?.display_name,
     })
     .then(() => {
       jitsu.track(eventName, {