feat(windows): add option to download updates on metered connection.

As follow on from #13566 which will not download updates in the background when on a metered connection. We could add a Keyman Configuration option to "allow bacgruond updates on metered connections." Windows allows people to set a data limit on metered connections. Theferfore they could be happy with updates as they are managing there data overall. This more of a polish to the metered connection download feature.