How to increase number of color categories?

```python
import hvplot.pandas
import datashader as ds
import holoviews as hv
import numpy as np

hv.extension("bokeh")

tst = pd.DataFrame({
"lon": np.random.randn(257),
"lat": np.random.randn(257),
"cat": np.random.randn(257).astype(str),
})
tst.hvplot.paths("lon", "lat", datashade=True, aggregator=ds.count_cat("cat"))
```
Crashes with
```python

WARNING:param.dynamic_operation: Callable raised "ValueError('Insufficient colors provided (256) for the categorical fields available (257)')".
Invoked as dynamic_operation(height=300, scale=1.0, width=700, x_range=None, y_range=None)
```