cmd/devp2p: tweak DNS TTLs (#20801)

* cmd/devp2p: tweak DNS TTLs

* cmd/devp2p: bump treeNodeTTL to four weeks

cmd/devp2p/dnscmd.go

@@ -97,8 +97,8 @@ var (
 )
 
 const (
-	rootTTL     = 1
-	treeNodeTTL = 2147483647
+	rootTTL     = 30 * 60              // 30 min
+	treeNodeTTL = 4 * 7 * 24 * 60 * 60 // 4 weeks
 )
 
 // dnsSync performs dnsSyncCommand.