oegedijk/explainerdashboard: V0.4.7: categorical bug fixes

<h2>Version 0.4.7:</h2> <h3>Bug Fixes</h3> <ul> <li>fix merge_categorical_columns when there are no cats</li> <li>Handle pandas option setting context in case it doesn't exist</li> <li>Remove is_categorical_dtype as it is getting deprecated</li> </ul&gt