Edit + upload attachment + delete right away (without leaving draft mode) leaves the attachment in the storage target

[lisajulia]

When using a storage target (i.e. cds-feature-attachments-fs for the local file system or cds-feature-attachments-oss for an external object store service), I saw the following problem:

edit an existing entity that can have attachments (enter draft mode)
upload an attachment (still in draft mode)
delete that attachment (still in draft mode)
=> This leaves the attachment in the storage target and does not delete it from there.