avoid showing invalid fringe color when color is invalid

Author: ericdallo

lsp-dart-flutter-fringe.el

@@ -81,10 +81,10 @@ Increase for a better performance."
     (save-excursion
       (goto-char (point-min))
       (while (re-search-forward lsp-dart-flutter-fringe-color-name-pattern nil t)
-        (let ((color (concat "#" (-> (match-string 1)
-                                     (assoc lsp-dart-flutter-colors)
-                                     cdr))))
-          (lsp-dart-flutter-fringe--add-color color buffer (point-at-bol))))
+        (if-let ((color (-> (match-string 1)
+                         (assoc lsp-dart-flutter-colors)
+                         cdr)))
+          (lsp-dart-flutter-fringe--add-color (concat "#" color) buffer (point-at-bol))))
       (goto-char (point-min))
       (while (re-search-forward lsp-dart-flutter-fringe-color-hex-pattern nil t)
         (let ((color (concat "#" (substring (match-string 1) 2))))