docs: SwitchGoogle social auth to getClaims (#43593)

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

apps/docs/content/guides/auth/social-login/auth-google.mdx

@@ -395,11 +395,11 @@ const OneTapComponent = () => {
     console.log('Nonce: ', nonce, hashedNonce)
 
     // check if there's already an existing session before initializing the one-tap UI
-    const { data, error } = await supabase.auth.getSession()
+    const { data: { claims }, error } = await supabase.auth.getClaims()
     if (error) {
-      console.error('Error getting session', error)
+      console.error('Error getting claims', error)
     }
-    if (data.session) {
+    if (claims) {
       router.push('/')
       return
     }