Potential fix for code scanning alert no. 12: URL redirection from remote source

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: radishmouse

src/thunderbird_accounts/authentication/views.py

@@ -106,7 +106,7 @@ def sign_up(request: HttpRequest):
 
     if not is_email_in_allow_list(email):
         # Redirect the user to the tbpro waitlist
-        return HttpResponseRedirect(f'{settings.TB_PRO_WAIT_LIST_URL}?email={email}')
+        return HttpResponseRedirect(f'{settings.TB_PRO_WAIT_LIST_URL}?email={quote(email)}')
 
     # Make sure there's no email alias with this address
     if is_address_taken(username):