[Carry #1847] Fix zstd:chunked converter error on duplicated blobs

[ktock]

Carry #1847

This PR fixes the following warning by zstd:chunked converter. This PR fixes that issue by not cleaning up of temporary resources by our own but we rely on containerd's GC instead.

WARN[0038] failed to remove tmp uncompressed layer       error="content digest sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef: not found" uncompressedDesc="&{application/vnd.oci.image.layer.v1.tar sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef 1024 [] map[] [] <nil> }"

reporoducer:

# ctr-remote i pull docker.io/library/tomcat:10.1-jdk21-temurin-noble
# ctr-remote image optimize --oci --period=30 --zstdchunked docker.io/library/tomcat:10.1-jdk21-temurin-noble test

[ktock]

cc @apostasie