Fix alert serialization when opening incidents

As Sidekiq does not support ActionController::Parameters[1]
we have to convert them to a Hash when scheduling a job.

[1]: https://github.com/mperham/sidekiq/issues/3667

ee/app/services/projects/prometheus/alerts/notify_service.rb

@@ -133,7 +133,7 @@ module Projects
         def process_incident_issues
           firings.each do |alert|
             IncidentManagement::ProcessAlertWorker
-              .perform_async(project.id, alert)
+              .perform_async(project.id, alert.to_h)
           end
         end
 

ee/spec/services/projects/prometheus/alerts/notify_service_spec.rb

@@ -29,16 +29,18 @@ describe Projects::Prometheus::Alerts::NotifyService do
     end
   end
 
-  shared_examples 'processes incident issues' do |amount|
+  shared_examples 'processes incident issues', :sidekiq do |amount|
     let(:create_incident_service) { spy }
 
     it 'processes issues' do
       expect(IncidentManagement::ProcessAlertWorker)
         .to receive(:perform_async)
-        .with(project.id, anything)
+        .with(project.id, kind_of(Hash))
         .exactly(amount).times
 
-      expect(subject).to eq(true)
+      Sidekiq::Testing.inline! do
+        expect(subject).to eq(true)
+      end
     end
   end