Await auth request when calling signOut

[kmjennison]

The signOut method signs out the user on on the Firebase JS SDK but it does not await the "logout" API request. This can cause unexpected behavior.

From discussion: #556

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On our index page I have a top menu which hosts the Sign Out button.
The onClick of Sign Out looks like this.

const router = useRouter()
const signOut = async () => {
    await authUser.signOut()
    router.reload()
  }

I expected this to change my index page context, on the router.reload of the page. But at this time I still the authUser.id being present even after reload.
The page only works correctly when I click a manual refresh on browser.

export const getServerSideProps = withAuthUserTokenSSR()(async context => {
  let isAuthenticated = false
  const authUser = context.AuthUser
  if (authUser.id) {
    console.log(authUser.id)
    isAuthenticated = true
  }
return {
    props: {
      isAuthenticated,
    },
  }
}

How can I reflect the correct logout state to my SSR page for updating the UI for a guest user?

Originally posted by @ahetawal-p in #556