Allow visual reviews to work on private/internal projects

What does this MR do?

Solves #42750 (closed)

Currently, visual reviews only work on public projects. This MR aims to fix this.

The solution here is based on the discussion #42750 (comment 307131748)

While this allows sending visual review feedback to private/internal projects, this also allows anyone who has access to the review app URL to comment. But according to #42750 (comment 307252035), this is fine.

Screenshots

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