refactor: use onServerResponse for auth instead of server api

wp-content/themes/ccat/app/graphql/login.gql

@@ -0,0 +1,10 @@
+mutation login($email: String!, $password: String!) {
+  login(input: { username: $email, password: $password }) {
+    authToken
+    refreshToken
+    user {
+      id
+      email
+    }
+  }
+}