Problem with WebPDF in a conda environment

Hello,

I tried using both the command line and the Jupyter menu to export a notebook as a WebPDF and encountered errors in both cases. The web interface returned a 500 error and told me to install `nbconvert[webpdf]`, which I did. The problems continued, but after looking into it I discovered that I needed to install `playwright`, also.

I am using a `conda` environment, originally with just the `conda-forge` and the `defaults` channels. I discovered that `playwright` is not [available](https://anaconda.org/search?q=playwright) on either channel, so I added the Microsoft channel. Then, the command-line version of `nbconvert` returned the error message, ``RuntimeError: No suitable chromium executable found on the system. Please use '--allow-chromium-download' to allow downloading one,or install it using `playwright install chromium`.`` Finally, I added that flag, running `nbconvert` again downloaded chromium, and now I am able to export to WebPDF using both the command line and the Jupyter menu commands.

Is this anomalous behavior? Is a fix available?