Remove (dead) instance level Value Stream Analytics page code

What does this MR do?

This MR removes the instance level Value Stream Analytics page, which is no longer in use after these MRs merged:

• !39368 (merged)
• !41580 (merged)

Some (legacy) tests take too long time to run to pass locally. Particularly under the test group:

• "Cycle Analytics component › displays the components as required › the user has access to the group"

This MR won't handle those.

Screenshots

N/A

It should work as before since this code is not being used.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

This MR does involve some risk as it removes legacy code that is no longer being used. However, tests have been updated to show that they conform to expected behavior.

To test this out run this seed SEED_CYCLE_ANALYTICS=true bundle exec rake db:seed_fu FILTER=cycle_analytics and navigate here:

• http://localhost:3000/groups/vsmg-1599662389/-/analytics/value_stream_analytics
• http://localhost:3000/vsmg-1599662389/vsmp-1599662389/-/value_stream_analytics

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

Closes #230631 (closed) Closes #223735 (closed)