fix: filter result if exported data is empty

internal/browingdata/localstorage/localstorage.go

@@ -58,6 +58,10 @@ func (c *ChromiumLocalStorage) Name() string {
 	return "localStorage"
 }
 
+func (c *ChromiumLocalStorage) Length() int {
+	return len(*c)
+}
+
 func (s *storage) fillKey(b []byte) {
 	keys := bytes.Split(b, []byte("\x00"))
 	if len(keys) == 1 && bytes.HasPrefix(keys[0], []byte("META:")) {
@@ -142,3 +146,7 @@ func (s *storage) fillFirefox(originKey, key, value string) {
 func (f *FirefoxLocalStorage) Name() string {
 	return "localStorage"
 }
+
+func (f *FirefoxLocalStorage) Length() int {
+	return len(*f)
+}