PosthogAnalytics unwatch settings on logout (#11207)

* PosthogAnalytics unwatch settings on logout

* Tidy

src/Lifecycle.ts

@@ -748,11 +748,12 @@ let _isLoggingOut = false;
  * Logs the current session out and transitions to the logged-out state
  */
 export function logout(): void {
-    if (!MatrixClientPeg.get()) return;
+    const client = MatrixClientPeg.get();
+    if (!client) return;
 
     PosthogAnalytics.instance.logout();
 
-    if (MatrixClientPeg.get()!.isGuest()) {
+    if (client.isGuest()) {
         // logout doesn't work for guest sessions
         // Also we sometimes want to re-log in a guest session if we abort the login.
         // defer until next tick because it calls a synchronous dispatch, and we are likely here from a dispatch.
@@ -761,7 +762,6 @@ export function logout(): void {
     }
 
     _isLoggingOut = true;
-    const client = MatrixClientPeg.get()!;
     PlatformPeg.get()?.destroyPickleKey(client.getSafeUserId(), client.getDeviceId() ?? "");
     client.logout(true).then(onLoggedOut, (err) => {
         // Just throwing an error here is going to be very unhelpful