docs(auth): log the token value in the idToken example

[armando-navarro]

The idToken example's subscription logs string, which is a type name rather than a value in that scope, so the snippet would not compile if copied. This logs the token parameter the callback actually receives, matching the neighboring authState example.

This is a reland of #3652 by @saadlalam, whose original fix was correct but could not be merged because the CLA check never cleared on that branch. The fix is theirs; relanding it here so it isn't lost. While here, it also corrects the comment on the line above, which was copied from the authState example and referred to a user rather than the token this example streams.

[tyler-reitz]

Correct — string is a type name in that scope, so the snippet couldn't compile as written. Logging the token parameter matches the neighboring authState example, and fixing the copied comment along with it is the right call.

Thanks for relanding @saadlalam's fix rather than letting it get lost to the stalled CLA check.

[armando-navarro]

Thanks Tyler. Relanding it seemed better than losing a correct fix to a CLA check the author had no way to move.