remove `supertokens-auth-react` dependency

After getting rid of the supertokens-node and supertokens-core dependency (https://github.com/graphql-hive/console/pull/7699; https://github.com/graphql-hive/console/pull/7705). We can now also get rid of `supertokens-auth-react` on the frontend and be in full control of the authentication flow.