feat: manifest debug for reusable-docker-build-publish

[erikburt]

Related to #1564.

Motivation

We are trying to root cause an issue where we are seeing intermittent 255 exit codes during the: docker buildx imagetools create command.
AFAICT the manifest index, and annotations are pushed correctly. Without these logs on an actual run, we will not be able to come to a proper conclusion as to why it's failing.

This is not the ideal scenario, but I didn't realize top-level workflow env vars were not propagated to reusable workflows. So this is where we are now.

We can treat this behaviour as temporary, and remove the input in the future.