[ci] Add heat tempest tests to autoscaling-tempest job

Autoscaling feature rely on heat working. Adding the heat-tempest-plugin would help to ensure this dependency is working as expected.

Author: elfiesmelfie

ci/vars-autoscaling-tempest.yml

@@ -27,6 +27,7 @@ cifmw_test_operator_tempest_include_list: |
   ^tempest.*\[.*\bsmoke\b.*\]
   telemetry_tempest_plugin.scenario
   telemetry_tempest_plugin.aodh
+  ^heat_tempest_plugin.*
 cifmw_test_operator_tempest_exclude_list: |
   telemetry_tempest_plugin.scenario.test_telemetry_integration_prometheus.PrometheusGabbiTest.test_autoscaling
 external_plugin: "opendev.org/openstack/telemetry-tempest-plugin"