rxui.select has KeyError: 'error'

```python
from ex4nicegui import rxui, to_ref


name = to_ref("")
options = ["a", "b"]

rxui.select(options, value=name)
rxui.label(text=name)
ui.button("change", on_click=lambda: name.set_value("other"))
```

error:
```
    if self._error == error and self._props['error'] == new_error_prop:
                                ~~~~~~~~~~~^^^^^^^^^
KeyError: 'error'
```