Fix macOS DNS unclean shutdown restore call on startup (#2286)

previously, we called the restore method from the startup when there was an unclean shutdown. But it never had the state keys to clean since they are stored in memory

this change addresses the issue by falling back to default values when restoring the host's DNS

client/internal/dns/host_darwin.go

@@ -110,19 +110,17 @@ func (s *systemConfigurator) applyDNSConfig(config HostDNSConfig) error {
 }
 
 func (s *systemConfigurator) restoreHostDNS() error {
-	lines := ""
-	for key := range s.createdKeys {
-		lines += buildRemoveKeyOperation(key)
+	keys := s.getRemovableKeysWithDefaults()
+	for _, key := range keys {
 		keyType := "search"
 		if strings.Contains(key, matchSuffix) {
 			keyType = "match"
 		}
 		log.Infof("removing %s domains from system", keyType)
-	}
-	_, err := runSystemConfigCommand(wrapCommand(lines))
-	if err != nil {
-		log.Errorf("got an error while cleaning the system configuration: %s", err)
-		return fmt.Errorf("clean system: %w", err)
+		err := s.removeKeyFromSystemConfig(key)
+		if err != nil {
+			log.Errorf("failed to remove %s domains from system: %s", keyType, err)
+		}
 	}
 
 	if err := removeUncleanShutdownIndicator(); err != nil {
@@ -132,6 +130,19 @@ func (s *systemConfigurator) restoreHostDNS() error {
 	return nil
 }
 
+func (s *systemConfigurator) getRemovableKeysWithDefaults() []string {
+	if len(s.createdKeys) == 0 {
+		// return defaults for startup calls
+		return []string{getKeyWithInput(netbirdDNSStateKeyFormat, searchSuffix), getKeyWithInput(netbirdDNSStateKeyFormat, matchSuffix)}
+	}
+
+	keys := make([]string, 0, len(s.createdKeys))
+	for key := range s.createdKeys {
+		keys = append(keys, key)
+	}
+	return keys
+}
+
 func (s *systemConfigurator) removeKeyFromSystemConfig(key string) error {
 	line := buildRemoveKeyOperation(key)
 	_, err := runSystemConfigCommand(wrapCommand(line))