Fix the definitions for Lead Time and Cycle Time

What does this MR do?

These definitions for Cycle Time and Lead Time were accidentally reversed. This simply switches them so they are correct. A separate MR fixes the in-app definitions.

Sources:

• https://docs.microsoft.com/en-us/azure/devops/report/dashboards/cycle-time-and-lead-time?view=azure-devops
• https://clickup.com/blog/cycle-time-vs-lead-time/
• https://efinancemanagement.com/financial-management/lead-time-and-cycle-time
• https://www.latestquality.com/lead-time-vs-cycle-time/

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because this is documentation only.
• 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
• 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