refactor: simplify notification messages for offer viewing

- Remove conditional notification logic in NewActivityView
- Remove redundant notification in RecentOffersToUserView and RecentOffersToUserProjectsView
- Standardize to single notification message format

src/views/RecentOffersToUserProjectsView.vue

@@ -148,7 +148,6 @@ export default class RecentOffersToUserView extends Vue {
           lastAckedOfferToUserProjectsJwtId:
             this.newOffersToUserProjects[0].jwtId,
         });
-        this.notify.info("The offers are marked as viewed.", TIMEOUTS.LONG);
       }
 
       // eslint-disable-next-line @typescript-eslint/no-explicit-any