Add permissions to see Dependency List page

What does this MR do?

If the user doesn't have access to Dependency List page (for example, a public project with the private repository) we should render 404 error. Right now we render the page and show an error that "Error while fetching dependencies" and this page isn't available in the menu, you can access it only by link.

This MR fixes it and improves a little test cases (use report access level as it's lower access level with right permission, test both for public and private projects).

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

Performance 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