chore(client): Log the LSN as base64 instead of bytes

[davidmartos96]

This is a minor change but it can end up being helpful during debugging. It will display the LSN in the base64 version instead of an array of numbers. There are other places in the client that log it as base64, and this one seems to be the only one that displays it as bytes.

[KyleAMathews]

👋 we've been working the last month on a rebuild of the Electric server over at a temporary repo https://github.com/electric-sql/electric-next/

You can read more about why we made the decision at https://next.electric-sql.com/about

We're really excited about all the new possibilities the new server brings and we hope you'll check it out soon and give us your feedback.

We're now moving the temporary repo back here. As part of that migration we're closing all the old issues and PRs. We really appreciate you taking the time to investigate and create this improvement!