fix(firewall): delete chain rules by line number (#2411)

- Fix #2334 
- Parsing of iptables chains, contributing to progress for #1856

internal/firewall/logger.go

@@ -5,12 +5,6 @@ import (
 	"net/netip"
 )
 
-type Logger interface {
-	Debug(s string)
-	Info(s string)
-	Error(s string)
-}
-
 func (c *Config) logIgnoredSubnetFamily(subnet netip.Prefix) {
 	c.logger.Info(fmt.Sprintf("ignoring subnet %s which has "+
 		"no default route matching its family", subnet))