Use the composable useSignInIdToken to sign in a user using an idToken. 
const { signInIdToken, isLoading, isSuccess, isError, error } =
  useSignInIdToken()

console.log({ isLoading, isSuccess, isError, error })

const handleSignInIdToken = async () => {
  await signInIdToken({ provider: 'google', idToken: '...' })
}