Use authorization DSL

This avoids reimplementing the DSL functionality, but is functionally
equivalent.

app/graphql/resolvers/projects/jira_projects_resolver.rb

@@ -6,6 +6,7 @@ module Resolvers
       include Gitlab::Graphql::Authorize::AuthorizeResource
 
       type Types::Projects::Services::JiraProjectType.connection_type, null: true
+      authorize :admin_project
 
       argument :name,
                GraphQL::STRING_TYPE,
@@ -31,10 +32,6 @@ module Resolvers
         end
       end
 
-      def authorized_resource?(project)
-        Ability.allowed?(context[:current_user], :admin_project, project)
-      end
-
       private
 
       alias_method :jira_service, :object