Geo: Check for a current node in `rake gitlab:geo:check`

What does this MR do?

Resolves #13352 (closed)

Example success case:

Example failure case (I changed current_node_name to something wrong):

Screenshots

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.