Authorize access to view license scan reports

What does this MR do?

This change add tests to ensure that a viewer is allowed to view a license scan report from forked projects.

The screenshot below shows two browsers side by side. In the browser on the left the user xlgmokha (maintainer) is logged in and viewing the merge request that was submitted by contributor from contributor/208723-bug to xlgmokha/208723-bug. The browser on the left shows the same merge request from the perspective of the contributor user.

Related to:

• #208723 (closed)

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