🐛(frontend) prevent Crisp crash when superuser has no email

Fix crash when switching from admin session to app with superuser account
that lacks email field. Add null check to prevent Crisp initialization
errors.

src/frontend/src/features/support/hooks/useSupport.tsx

@@ -7,7 +7,7 @@ export const initializeSupportSession = (user: ApiUser) => {
   if (!Crisp.isCrispInjected()) return
   const { id, email } = user
   Crisp.setTokenId(`meet-${id}`)
-  Crisp.user.setEmail(email)
+  if (email) Crisp.user.setEmail(email)
 }
 
 export const terminateSupportSession = () => {