Improve Ledger blind-signing copy

Per tweet: https://twitter.com/spengrah/status/1486420961880588291?s=20

Currently if blind-signing is disabled on the Ledger device, the error says:
> "Please enable Blind signing or Contract data in the Ethereum app Settings"

It should specify what Ethereum app and settings we're referring to. Like:
> "To sign transactions with your Ledger, you must enable blind signing on the Ledger. On the device: open the Ethereum app, then settings, and enable Blind signing or Contract data"

Search the repository for the current error text, "Please enable Blind signing or Contract data in the Ethereum app Settings," and inspect the Ledger blind-signing error path. Update the user-facing copy to identify the Ledger device, Ethereum app, settings, and Blind signing or Contract data option, then verify the resulting error message.

Written by the indexing model from the issue text.