Attachments bundle generation fails when database contains references to deleted files

In some cases, when generating the attachments bundle, the operation fails because certain files referenced by the instance no longer exist in storage. As a result, the bundle process stops and the ZIP file is not produced. The system should be able to complete the bundle generation by ignoring missing files, instead of failing the entire operation.

Steps to Reproduce:

1. Have attachments referenced in the database that were deleted from S3.
2. Try to generate the attachments bundle.
3. The operation fails.

Expected Behavior: The attachments bundle should still be generated successfully, skipping missing files.

Actual Behavior: The process fails when one or more referenced files are not found in S3.