Add cycle analytics scatterplot ff

What does this MR do?

Push the feature flag used for the cycle analytics duration chart to the fronted.

Frontend MR: !14996 (merged) Backend MR: !19293 (merged)

Screenshots

The feature flag will be used to toggle the chart highlighted below. Tests for this flag will be included in the MR that uses the feature flag.

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

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers

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