DEV: Resolve user_option deprecation (#23082)

Setting user_options directly on the user object is deprecated (see https://github.com/discourse/discourse/blob/0b56af6f58/app/assets/javascripts/discourse/app/models/user.js#L150-L165). We're already setting it in the correct way a few lines later, so this line can be removed.

app/assets/javascripts/discourse/app/instance-initializers/user-tips.js

@@ -33,8 +33,6 @@ export default {
       return;
     }
 
-    this.currentUser.set("seen_popups", seenUserTips);
-
     if (!this.currentUser.user_option) {
       this.currentUser.set("user_option", {});
     }