chore: bump version to 2.21.6 in package.json and enhance captcha integration across auth components (#418)

- Updated application version from 2.21.4 to 2.21.6 in package.json.
- Added "verifyingCaptcha" message to auth.json for improved user feedback during captcha verification.
- Enhanced captcha handling in various authentication components, including MagicLinkAuthContainer, PasswordResetRequestContainer, and SignUpContainer, to reflect loading states and improve user experience.

packages/features/auth/src/captcha/client/use-captcha.tsx

@@ -67,15 +67,20 @@ export function useCaptcha(
     [siteKey, nonce, handleTokenChange, handleInstanceChange],
   );
 
+  // Ready when captcha is not configured (no siteKey) or token is available
+  const isReady = !siteKey || token !== '';
+
   return useMemo(
     () => ({
       /** The current captcha token */
       token,
+      /** Whether the captcha is ready (not configured or token available) */
+      isReady,
       /** Reset the captcha (clears token and resets widget) */
       reset,
       /** The captcha field component to render */
       field,
     }),
-    [token, reset, field],
+    [token, isReady, reset, field],
   );
 }