Typedoc of ui-extension shows internal classes

The generated Typedoc in the release/13.2 branch of the ui-extension library shows all internal classes. That should not happen.

Steps to reproduce:

1. npm run docs
2. open docs/index.html in a browser

Expected: the list of globals only contains the class 'UiExtension'

Actual: the list of globals also contains internal classes like Channel, ParentConnection, etc (see screenshot).

Compare with the online typedoc to see the difference: https://javadoc.onehippo.org/13.0/bloomreach-ui-extension/