Task "Copy the Google Cloud service account configuration file" should be optional

[cmd-ntrf]

Currently, when running the playbook, the following error occurs:

TASK [Copy the Google Cloud service account configuration file] *********************************************
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: If you are using a module and expect the file to exist on the remote, see the remote_src option
fatal: [beluga.mc.computecanada.dev]: FAILED! => {"changed": false, "msg": "Could not find or access '/Users/xxxxxx/xx/x.x.x.x/gcloud-key.json' on the Ansible Controller.\nIf you are using a module and expect the file to exist on the remote, see the remote_src option"}

when gcloud-key.json is missing while the README does not mention we are forced to configured Google Cloud DNS key for MC-Hub to work.