Function decrypt_attachments_with_failures 

pub(crate) fn decrypt_attachments_with_failures(
    attachments: &[Attachment],
    ctx: &mut KeyStoreContext<'_, KeySlotIds>,
    key: SymmetricKeySlotId,
) -> (Vec<AttachmentView>, Vec<AttachmentView>)

Decrypts a list of attachments, separating successful decryptions from failures.

Returns a tuple of (successful_attachments, failed_attachments).