[Docs] Reference to `playground2` application is invalid

[JayaShakthi97]

Is your suggestion related to a missing or misleading document? Please describe.

The link to setup playground2 application mentioned under "Configure ACR-based adaptive authentication" throws 404.

1. Visit following; https://is.docs.wso2.com/en/latest/guides/authentication/conditional-auth/acr-based-adaptive-auth/#prerequisites:~:text=You%20can%20register%20your%20own%20application%20or%20use%20the
2. Click on playground2 link
3. Better check other places as well.

Describe the improvement

Need to be updated with the proper link.

[JayaShakthi97]

For reference: There's a latest release aimed for IS 7.0 https://github.com/wso2/samples-is/releases/tag/v4.6.2