Signs the user in using third party OAuth providers.
auth.signInWithProvider()is only available on
- It will open the browser to the relevant login page.
Specify the redirect link to bring back the user via deeplink.
redirectTo should be null for Flutter Web.
If you need additional data from an OAuth provider, you can include a space-separated list of scopes in your request to get back an OAuth provider token. You may also need to specify the scopes in the provider's OAuth app settings, depending on the provider.