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

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

const handleFormSubmit = async (e) => {
  e.preventDefault()

  await signInIdToken({ provider: 'google', idToken: '...' })
}