Removed Product_analytics related graphql & specs

What does this MR do and why?

• product_analytics feature category is decided to be deprecated and removed.
• The feature hasn't been GA to the users yet.
• It is currently disabled under the feature flag turned OFF
• As per this initiative Remove Product Analytics Category, we're planning to remove the implementation logic and the testing specs related to this feature.
• The code cleanup will be carried out in multiple iterations - component wise

What does this MR do

• This MR removes
  • The backend logics supporting the graphql end points
  • Front-end invocation points to the product analytics graphql api calls that includes the mutations and queries
  • backend and front end specs related to these areas

References

https://gitlab.com/groups/gitlab-org/-/work_items/17677+

https://gitlab.com/groups/gitlab-org/-/work_items/17195+

Screenshots or screen recordings

How to set up and validate locally

• Analytics page should not be broken:
  1. Go to any Projects
  2. From the side pane, Analyze -> Analytics dashboard
     1. The page should not be broken and should be able to load
• The PR build checks and tests should be passed - all green 🟢

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #599958