[code typo] Error in React Sample for Custom Auth Challenge with Google reCaptch

**Describe the content issue**:
The React Sample for Custom Auth Challenge with Google reCaptcha has custom component - `CaptchaConfirmSignIn` defined but is referenced incorrectly - `CaptchaConfirmation`. We also might need to `setShowCaptcha(true)` in `handleSignIn`method.

**URL page where content issue is**: https://docs.amplify.aws/javascript/tools/cli/usage/lambda-triggers/#custom-auth-challenge-with-google-recaptcha