message: check_grad_enabled only complains in record mode
diff: @@ -2351,7 +2351,7 @@ def traverse(t, mode, flags=_ek.ADFlag.Default):
  def _check_grad_enabled(name, t, a):
  if _ek.is_diff_array_v(t) and t.IsFloat:
  - if not grad_enabled(a):
  + if _ek.flag(_ek.JitFlag.VCallRecord) and not grad_enabled(a):
  raise Exception(
  f'{name}(): the argument does not depend on the input '
  'variable(s) being differentiated. Raising an exception '
  