Facter error when host has Podman

## Describe the Bug
When a server has podman installed it gets the following error
`Error: Facter: Error while resolving custom fact fact='docker', resolution='<anonymous>': undefined method `[]' for nil:NilClass`

## Expected Behavior
No error should appear

## Steps to Reproduce
Install Podman and have Puppet agent load the docker module

## Environment
RHEL 9
