Ignore rake task license check on geo secondaries

What does this MR do?

When validating a Geo installation, a secondary site application node will always fail the gitlab:geo:check rake task until it is joined because it expects a license.

This alters the behavior to note that a secondary does not need a license, per the documentation, and allows it to pass. The check will still ensure that a license must be present on the primary site application node.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.