Refactor RSVP cancellation and update methods to handle 404 responses gracefully

Author: rsmithlal

app/controllers/better_together/events_controller.rb

@@ -44,7 +44,10 @@ def rsvp_going
     end
 
     def rsvp_cancel
-      @event = set_resource_instance
+      set_resource_instance
+      return if performed? # Exit early if 404 was already rendered
+      
+      @event = @resource
       authorize @event, :show?
 
       # Ensure current_person exists
@@ -92,7 +95,10 @@ def resource_class
 
     # rubocop:todo Metrics/MethodLength
     def rsvp_update(status) # rubocop:todo Metrics/AbcSize, Metrics/MethodLength
-      @event = set_resource_instance
+      set_resource_instance
+      return if performed? # Exit early if 404 was already rendered
+      
+      @event = @resource
       authorize @event, :show?
 
       # Check if event allows RSVP

spec/requests/better_together/calendars_controller_spec.rb

@@ -11,7 +11,7 @@
   end
 
   context 'when viewing calendar show page' do
-    let(:calendar) { create('better_together/calendar') }
+    let(:calendar) { create('better_together/calendar', privacy: 'public') }
     let(:upcoming_event) do
       BetterTogether::Event.create!(
         name: 'Upcoming',