Fix reading the status of a secondary Geo node from the primary

What does this MR do?

Adds two attributes in the GeoNodeStatus entity to the separate whitelist held in Geo::NodeStatusService and improve tests to prevent a recurrence of this kind of regression.

Without this addition, the primary's instance of GeoNodeStatus will contain nil for these attributes, causing it to act as a secondary and attempt to call the lookup code. This leads to an exception in production, but a silent failure in development (GDK primary has a tracking database, so it "works", returning 0 failures)

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Regression in code already picked into %10.1 - https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/3101 and 10.1 MR.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #3742 (closed)