Fix problem with running scheduled policies when variables are empty

ee/app/services/security/security_orchestration_policies/ci_configuration_service.rb

@@ -49,14 +49,14 @@ module Security
 
       def child_pipeline_configuration(template, ci_variables)
         {
-          variables: ci_variables.compact,
+          variables: ci_variables.compact.presence,
           inherit: {
             variables: false
           },
           trigger: {
             include: [{ template: "#{SCAN_TEMPLATES[template.to_s]}.gitlab-ci.yml" }]
           }
-        }
+        }.compact
       end
 
       def error_script(error_message)

ee/spec/services/security/security_orchestration_policies/ci_configuration_service_spec.rb

@@ -129,6 +129,19 @@ RSpec.describe Security::SecurityOrchestrationPolicies::CiConfigurationService d
 
           expect(subject).to eq(expected_configuration)
         end
+
+        context 'when variables are empty' do
+          let_it_be(:ci_variables) { {} }
+
+          it 'returns prepared CI configuration for SAST' do
+            expected_configuration = {
+              inherit: { variables: false },
+              trigger: { include: [{ template: 'Security/SAST.gitlab-ci.yml' }] }
+            }
+
+            expect(subject).to eq(expected_configuration)
+          end
+        end
       end
     end