Delete AnnotationsFinder class

What does this MR do and why?

Deletes AnnotationsFinder class.

Deletes its usage in Resolver and updates/deletes specs.

Helps #397139 (closed) move forward.

Screenshots or screen recordings

NA

How to set up and validate locally

1. The Annotations GQL API was returning nil as remove_monitor_metrics FF was default enabled.
2. This was the only place this finder class was used, so the functionality is the same, but it will return empty response even if the flag is enabled.

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 #397139 (closed)