startup-regtest: only inspect current run's logs for clnrest updates

If you re-run a node several times, the log file fills with info from
previous runs. To avoid looking at old logs, only parse the most recent
run's logs when looking for the magic CLN rest startup/deactivated
strings

Changelog-Fixed: startup-regtest.sh now only inspects the most recent run's logs for the active status of the clnrest plugin

contrib/startup_regtest.sh

@@ -143,9 +143,9 @@ clnrest_status() {
 	active_str="plugin-clnrest: REST server running"
 	disabled_str="plugin-clnrest: Killing plugin: disabled itself"
 
-	if grep -q "$active_str" "$logfile"; then
+	if grep -n "Opened log file" "$logfile" | cut -d : -f 1 | tail -1 | xargs -I{} tail -n +{} "$logfile" | grep -q "$active_str"; then
 		echo "active"
-	elif grep -q "$disabled_str" "$logfile"; then
+	elif grep -n "Opened log file" "$logfile" | cut -d : -f 1 | tail -1 | xargs -I{} tail -n +{} "$logfile" | grep -q "$disabled_str"; then
 		echo "disabled"
 	else
 		echo "waiting"