Remove Feature Flag License Check RUN AS-IF-FOSS

What does this MR do?

Remove the license check for feature flags.

This MR makes Feature Flags available in GitLab Enterprise edition with any Starter, Premium, or Ultimate license. Feature Flags are also available in Enterprise Edition without a license. Feature Flags are still not available in GitLab FOSS.

Keep a license check for Feature Flag Related Issues. This feature is available only in Premium and Enterprise.

This is part of moving feature flags to Core.

Issue: #212318 (closed)

Screenshots

GitLab Enterprise Edition with an Ultimate or Premium License

• The Feature Flags menu exists:

• The index page exists:

• The feature flag edit page displays the linked issues widget:

• Creating, deleting, and editing flags works. Unleash clients can request flags.

GitLab Enterprise Edition with Starter or No License

• The Feature Flags menu exists:

• The index page exists:

• The feature flag edit page does not display the linked issues widget:

• Creating, deleting, and editing flags works. Unleash clients can request flags.

GitLab FOSS

• The Feature Flags menu does not exist:

• The index page does not exist:

• The feature flag edit page does not exist:

• Creating, deleting, and editing flags does not work. Unleash clients cannot request flags. They receive a 404.

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
• 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