Add license ID to license view

What does this MR do?

This MR adds a license ID list item to the license details page /admin/license on EE instances.

Why is it needed?

The license ID can (soon) be used by support to search for license details. In support it's useful to know exactly what instance we're supporting (from a licensing perspective). I talked this over with several folks in support, including @lbot and @lyle, and we agreed this would be useful.

Future integrations used by GitLab Support could also use this License ID as an identifier and source of truth. That aside, I think exposing the ID in the UI is useful enough for now.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• 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