We should output if chown is successful or not

[cdrage]

https://github.com/osbuild/bootc-image-builder/blob/7c6cffcd84ab0db22448d66cd2a107daff976bc6/bib/cmd/bootc-image-builder/main.go#L495

Unlike other outputs, we do not know if chown was succesful or not which is useful for debugging / output purposes