Installation script fails on OCI instances

If you're installing agents using installation script on an OCI instance that doesn't belong to the same tenancy or region as that of your fleet, then your installation fails with the
```
Script <<script-name>> failed to get Instance Config for <<OCID>>
```
message.
Rerun the script with parameter --install-mgmt-agent to force the installation of the Oracle Management Agent (which is meant for on-premise instances) instead of Oracle Cloud Agent.
If you're installing agents using an installation script on an OCI instance that belongs to the same tenancy or region as that of your fleet, then make sure you have the policy as described in Set up OCI Linux instances for JMS Fleets.