Update API::GeoNodes OpenApiV2 documentation

What does this MR do and why?

This MR updates outdated parts of OpenApiV2 documentation for API::GeoNodes

Related to #377024

Screenshots or screen recordings

How to set up and validate locally

Since rake gitlab:openapi:generate task shouldn't be run according to the issue description, only check updated annotations

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #377024