Disable trending argument on Projects GraphQL query

What does this MR do and why?

Disable the trending argument from the Projects GraphQL query, turning it into a no-op.

References

• Deprecation Entry: Trending tab in Explore > Projects is deprecated (!215948 - merged)
• Deprecation Issue: Deprecate the trending params from the Projects... (&20317)
• Breaking Change Exception Request: https://gitlab.com/gitlab-com/Product/-/issues/14440+
• Related to #583195 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Enable the disable_trending_args feature flag on http://127.0.0.1:3000/rails/features/
2. (Optional) Run TrendingProject.refresh! to update the list of trending projects. Tweak the MONTHS_TO_INCLUDE accordingly.
3. Go to http://127.0.0.1:3000/-/graphql-explorer and run the following query:

{
  projects(trending: true) {
    nodes {
      id
      name
    }
  }
}

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