Geo - Skip download of blobs with foreign layers

What does this MR do?

Some images contain layers that might have the media type application/vnd.docker.image.rootfs.foreign.diff.tar.gzip which are not present on the registry.

In this case, the client doesn't go to the registry to fetch the layer because it is not there but will follow the URL, specified among other details of the layer.

Geo should not try to fetch it from the registry during sync but skip this layer. It also does not want to follow the URL and download it because it might violate the license.

Does this MR meet the acceptance criteria?

Conformity

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  • I have not included a changelog entry because _____.
• Documentation (if required)
• Code review guidelines
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• 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

Related issues

Related to #329231 (closed)