Update controller query to avoid N+1

Also fix name of emitted event

ee/app/assets/javascripts/integrations/gitlab_slack_application/components/projects_dropdown.vue

@@ -35,7 +35,7 @@ export default {
   },
   methods: {
     onClick(project) {
-      this.$emit('projectSelected', project);
+      this.$emit('project-selected', project);
       this.$refs.dropdown.hide(true);
     },
   },

ee/app/controllers/profiles/slacks_controller.rb

@@ -10,7 +10,7 @@ class Profiles::SlacksController < Profiles::ApplicationController
   feature_category :users
 
   def edit
-    @projects = disabled_projects if current_user
+    @projects = disabled_projects.inc_routes if current_user
   end
 
   def slack_link

ee/spec/helpers/ee/integrations_helper_spec.rb

@@ -112,7 +112,7 @@ RSpec.describe EE::IntegrationsHelper do
     let_it_be(:projects) { create_list(:project, 3) }
 
     def relation
-      Project.id_in(projects.pluck(:id))
+      Project.id_in(projects.pluck(:id)).inc_routes
     end
 
     let(:request) do