Handle failure to verify refreshed token (#679)

If the existing token is expired, and we refresh it successfully, we
still need to call `veirfyIdToken` in order to get the `firebaseUser`,
which is required by `createUser` below.

Currently, if `verifyIdToken` with the newly refreshed token fails,
the error handler is called, but the code passes through, calling
`createUser` with a `token` but `firebaseUserAdminSDK: undefined`,
which causes the following error:

```
Error: The "token" value can only be set if the "firebaseUserAdminSDK" property is defined.
```

In order to prevent this, we need to set `newTokenFailure = true` in
case `verifyIdToken` fails with the newly refreshed token.

FWIW this never happened to me in production, but happens quite often
when developing with the Firebase emulators.

Co-authored-by: Kevin Jennison <kevin.jennison1@gmail.com>

src/firebaseAdmin.ts

@@ -153,6 +153,8 @@ export const verifyIdToken: VerifyIdToken = async (
                 } else {
                   logDebug(verifyErr)
                 }
+
+                newTokenFailure = true
               }
             }