fix(auth): Return empty map if token file does not exits, and refacto… (#12332)

Co-authored-by: Sandy Tao <sandytao520@icloud.com>

packages/cli/src/ui/AppContainer.tsx

@@ -433,6 +433,7 @@ Logging in with Google... Please restart Gemini CLI to continue.
   const handleApiKeySubmit = useCallback(
     async (apiKey: string) => {
       try {
+        onAuthError(null);
         if (!apiKey.trim() && apiKey.length > 1) {
           onAuthError(
             'API key cannot be empty string with length greater than 1.',