Enable heat support in telemetry-tempest-plugin

* Due to tempest plugin split migration and deprecation of
  `orchestration` flag in heat which is replaced with
  heat_plugins leads to skipping telemetry scenario tests.
* It updates the same and enable tests for the same.

Change-Id: Idd12dcb05322737b3d9b72eac902b969252ee4c3
4 files changed