"no bid received" info level log is misleading

At least myself and [one other person](https://www.reddit.com/r/ethstaker/comments/12enr2i/mevboost_msgno_bid_received/) have been a bit mislead during the debugging process of trying to figure out why a block was built locally.

In the event that no bids were received that exceed the min-bid setting, with log level set at the default (above debug), the user will see the info level log "no bid received" that is triggered in handleGetHeader if result.response.isEmpty is true.

In reality, bids may have actually been received, but the "bid received" and the potential subsequent "ignoring bid below min-bid value" logs from inside getHeader are at debug level, and won't show up at the default log level above debug.

The info level log from handleGetHeader if result.response.isEmpty is true should better reflect the real meaning of having result.response.isEmpty, which might be something like "no acceptable bids received" or something like that.