feat: add sign out ga event (freeCodeCamp#57150)

Author: ahmaxed

client/src/analytics/call-ga.ts

@@ -83,6 +83,11 @@ interface SignIn {
   event: 'sign_in';
 }
 
+interface SignOut {
+  event: 'sign_out';
+  user_id: undefined;
+}
+
 export type GAevent =
   | DonationViewEvent
   | DonationEvent
@@ -92,6 +97,7 @@ export type GAevent =
   | ExperimentViewEvent
   | ChallengeFailedEvent
   | UserData
+  | SignOut
   | SignIn;
 
 export default function callGA(payload: GAevent) {

client/src/components/signout-modal/index.tsx

@@ -8,6 +8,7 @@ import { Button, Modal, Spacer } from '@freecodecamp/ui';
 import { hardGoTo as navigate, closeSignoutModal } from '../../redux/actions';
 import { isSignoutModalOpenSelector } from '../../redux/selectors';
 import { apiLocation } from '../../../config/env.json';
+import callGA from '../../analytics/call-ga';
 
 const mapStateToProps = createSelector(
   isSignoutModalOpenSelector,
@@ -41,6 +42,7 @@ function SignoutModal(props: SignoutModalProps): JSX.Element {
 
   const handleSignout = () => {
     closeSignoutModal();
+    callGA({ event: 'sign_out', user_id: undefined });
     navigate(`${apiLocation}/signout`);
   };