NO-ISSUE: Upgrade docker-client to 25.x and remove deprecated tests

[ricardozanini]

Description of the change:

This issue involves manually upgrading Docker to the 25.x version, as done by our friend here #512. Part of this upgrade was to remove an outdated Heroku Docker client library that was being used by non-relevant rests in the container-builder package.

Also, there was a CVE in our main k8s dependency core, which was fixed too.

Motivation for the change:
Stay away from CVEs.

Checklist

• Add or Modify a unit test for your change
• Have you verified that tall the tests are passing?

How to backport a pull request to a different branch?

In order to automatically create a backporting pull request please add one or more labels having the following format backport-<branch-name>, where <branch-name> is the name of the branch where the pull request must be backported to (e.g., backport-7.67.x to backport the original PR to the 7.67.x branch).

NOTE: backporting is an action aiming to move a change (usually a commit) from a branch (usually the main one) to another one, which is generally referring to a still maintained release branch. Keeping it simple: it is about to move a specific change or a set of them from one branch to another.

Once the original pull request is successfully merged, the automated action will create one backporting pull request per each label (with the previous format) that has been added.

If something goes wrong, the author will be notified and at this point a manual backporting is needed.

NOTE: this automated backporting is triggered whenever a pull request on main branch is labeled or closed, but both conditions must be satisfied to get the new PR created.