Outdated Expo social‑auth docs links and redirects

# Improve documentation ## Describe the problem The frontend does not directly reference the wrong link, but it may exist as outdated metadata. Current redirects are also incorrect. Needs update to the canonical quickstart URL: https://supabase.com/docs/guides/auth/quickstarts/with-expo-react-native-social-auth. ## Outdated Links https://supabase.com/guides/getting-started/tutorials/with-expo-react-native-social-auth https://supabase.com/docs/guides/getting-started/tutorials/with-expo-react-native-social-auth http://supabase.com/docs/guides/with-expo-social-auth http://supabase.com/docs/guides/getting-started/tutorials/with-expo-social-auth ## Steps to Reproduce: Attempt to access Expo social‑auth docs via old links or redirects. Observe broken or misdirected pages. ## Describe the improvement All links and metadata should point to the canonical quickstart URL. ## Additional context Add any other context or screenshots that help clarify your question.