Promote reviewState and reviewStates GraphQL arguments to GA

What does this MR do and why?

The reviewState and reviewStates arguments on the mergeRequests GraphQL resolver have been marked as experiment since GitLab 17.0. They are now stable, widely used by the merge request dashboard, and have been in production for several milestones. This MR removes the experiment annotation to promote them to generally available.

The change has three parts:

• app/graphql/resolvers/merge_requests_resolver.rb: removes experiment: { milestone: '17.0' } from the review_state and review_states argument definitions.
• doc/api/graphql/reference/_index.md: regenerated reference docs, dropping the experiment badge everywhere these two arguments appear.
• public/-/graphql/introspection_result.json and public/-/graphql/introspection_result_no_deprecated.json: regenerated introspection dumps.

GitLab implements experiment status as a synthetic GraphQL deprecation, which is why the two introspection files change asymmetrically. In introspection_result.json, reviewState and reviewStates simply lose their deprecation metadata and the "Status: Experiment" suffix on their descriptions. In introspection_result_no_deprecated.json, the two arguments appear for the first time, because until now they were filtered out of that dump as deprecated. Both are the intended effect of going GA, not accidental changes.

References

• Original commit that introduced the field: a257f2c3

Screenshots or screen recordings

N/A — no UI change.

How to set up and validate locally

1. Run bundle exec rake gitlab:graphql:compile_docs and bundle exec rake gitlab:graphql:generate_all_introspection_schemas, then confirm there is no diff against the docs and introspection files committed in this MR. This is the same check the graphql-verify CI job runs via its check_docs and check_introspection_sync steps.
2. Run the resolver spec: bundle exec rspec spec/graphql/resolvers/merge_requests_resolver_spec.rb

MR acceptance checklist

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