Add command to rails console list for a self-managed license

What does this MR do?

Recently I encountered a customer who purchased an Ultimate self-managed license but removed all licenses from their instance. In determining their billable seat count we realized the normal method of checking this would likely include Guest seats in use since the normal billable seat check uses the tier of the subscription to complete the count. This rails command will filter Guest seats out for a more accurate count in those cases.

Related issues

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