Website: Update personalization in custom hook (#17324)

Changes:
- Updated the custom hook to not set
`req.session.primaryBuyingSituation` as undefined if a user does not
have a `utm_content` query parameter.

website/api/hooks/custom/index.js

@@ -155,14 +155,12 @@ will be disabled and/or hidden in the UI.
               req.session.primaryBuyingSituation = req.param('utm_content');
               // FUTURE: Auto-redirect without the querystring after absorbtion to make it prettier in the URL bar.
               // (except this probably messes up analytics so before doing that, figure out how to solve that problem)
-            } else {
-              req.session.primaryBuyingSituation = undefined;
-            }
+            }//fi
             if (req.method === 'GET') {
               // Include information about the primary buying situation
               // If set in the session (e.g. from an ad), use the primary buying situation for personalization.
               res.locals.primaryBuyingSituation = req.session.primaryBuyingSituation || undefined;
-            }
+            }//fi
 
             // Next, if we're running in our actual "production" or "staging" Sails
             // environment, check if this is a GET request via some other host,