Use @woocommerce/data instead of deprecated @woocommerce/settings package

[daledupreez]

While working on #4523, I discovered that the @woocommerce/settings package that we're using in the plugin has been deprecated - see https://www.npmjs.com/package/@woocommerce/settings for a very clear message. I then looked more closely and I think we should switch to the getSetting() function exposed from @woocommerce/data where possible.