Drop some "Channel does not qualify for a feerate change" logs

On a high-traffic/channel node, `Channel .* does not qualify for a
feerate change.*` is our most common log, and it doesn't provide
much useful information. It's logged in two cases - (a) where the
estimator feerate is less than the current channel feerate but not
by more than half twice and (b) where we'd like to update the
channel feerate but the peer is disconnected or channel not
available for updates.

Because these conditions can persist and we log them once a minute
the volume of logs can add up quickly. Here we simply remove the
log in case (a), though leave (b) as its anticipated to be somewhat
quieter and does indicate a persistent issue that should be
addressed (possibly by closing the channel).

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -4833,10 +4833,6 @@ where
 
 		// If the feerate has decreased by less than half, don't bother
 		if new_feerate <= chan.context.get_feerate_sat_per_1000_weight() && new_feerate * 2 > chan.context.get_feerate_sat_per_1000_weight() {
-			if new_feerate != chan.context.get_feerate_sat_per_1000_weight() {
-				log_trace!(logger, "Channel {} does not qualify for a feerate change from {} to {}.",
-				chan_id, chan.context.get_feerate_sat_per_1000_weight(), new_feerate);
-			}
 			return NotifyOption::SkipPersistNoEvents;
 		}
 		if !chan.context.is_live() {