buildah cache with --layers does not work when in RUN --mount=type=bind uses image or additional-build-context as source

[flouthoc]

Description

buildah cache with --layers does not work when in RUN --mount=type=bind uses image or additional-build-context as source

Steps to reproduce the issue:

1. Create a build where --mount=type=bind,source=.,dest=/somepath,from=<image> or --mount=type=bind,source=.,dest=/somepath,from=<additional-build-context>
2. Perform build with --layers
3. Perform build with --layers again.

Describe the results you received:
On second build, entire build must be cached.

Describe the results you expected:
Buildah does not uses cache on the second build.

Output of rpm -q buildah or apt list buildah:

(paste your output here)

Output of buildah version:

(paste your output here)

Output of podman version if reporting a podman build issue:

(paste your output here)

Output of cat /etc/*release:

(paste your output here)

Output of uname -a:

(paste your output here)

Output of cat /etc/containers/storage.conf:

(paste your output here)

[flouthoc]

Found this issue while working on #5691

[github-actions]

A friendly reminder that this issue had no activity for 30 days.

[flouthoc]

This is not stale, waiting on review here: #5693 (comment)