@Adarsh Shrivastav Thanks for reply! So to update the authentication settings for the webapp in the v2 format.
az webapp auth update [--action {AllowAnonymous, RedirectToLoginPage, Return401, Return403, Return404}]
[--config-file-path]
[--custom-host-header]
[--custom-proto-header]
[--enable-token-store {false, true}]
[--enabled {false, true}]
[--excluded-paths]
[--ids]
[--name]
[--proxy-convention {Custom, NoProxy, Standard}]
[--redirect-provider]
[--require-https {false, true}]
[--resource-group]
[--runtime-version]
[--set]
[--slot]
[--subscription]
Update the client ID of the AAD provider already configured
az webapp auth update -g myResourceGroup --name MyWebApp --set identityProviders.azureActiveDirectory.registration.clientId=my-client-id