fix(device): ensure chromecast parsing doesn't return null

[lbarthon]

This is supported by the JS library, but not by all the others. This sets the model to Chromecast, to prevent any possible error going on, as the model is needed in that regex.

Fixes #587

[migueldemoura]

@lbarthon as a follow-up when we have time, if null can't be used here because some libraries like the one #587 don't handle it, should we allow it in the first place?