gossipd, chanbackup: reduce logging levels

The vast majority of incoming channel updates seem to be cut due
to age, which results in noisy logs.  Similarly, the chanbackup
logging verbosity might better match the equivalent actions in
channeld, which are at the debug level.

Fixes: #8058

Changelog-None: introduced in 25.02

Author: endothermicdev

gossipd/gossmap_manage.c

@@ -824,7 +824,7 @@ static const char *process_channel_update(const tal_t *ctx,
 		u32 prev_timestamp
 			= gossip_store_get_timestamp(gm->gs, chan->cupdate_off[dir]);
 		if (prev_timestamp >= timestamp) {
-			status_debug("Too-old update for %s",
+			status_trace("Too-old update for %s",
 				     fmt_short_channel_id(tmpctx, scid));
 			/* Too old, ignore */
 			return NULL;

plugins/chanbackup.c

@@ -543,7 +543,7 @@ static struct command_result *after_staticbackup(struct command *cmd,
 	const jsmntok_t *scbs = json_get_member(buf, params, "scb");
 	struct out_req *req;
 	json_to_scb_chan(buf, scbs, &scb_chan);
-	plugin_log(cmd->plugin, LOG_INFORM, "Updating the SCB");
+	plugin_log(cmd->plugin, LOG_DBG, "Updating the SCB");
 
 	update_scb(cmd->plugin, scb_chan);
 	struct info *info = tal(cmd, struct info);