CI(build-build-tools): fix unexpected cancellations (#9357)

## Problem
When `Dockerfile.build-tools` gets changed, several PRs catch up with
it and some might get unexpectedly cancelled workflows because of
GitHub's concurrency model for workflows.
See the comment in the code for more details.

It should be possible to revert it after
https://github.com/orgs/community/discussions/41518 (I don't expect it
anytime soon, but I subscribed)

## Summary of changes
- Do not queue `build-build-tools-image` workflows in the concurrency
group

.github/workflows/build-build-tools-image.yml

@@ -19,9 +19,16 @@ defaults:
   run:
     shell: bash -euo pipefail {0}
 
-concurrency:
-  group: build-build-tools-image-${{ inputs.image-tag }}
-  cancel-in-progress: false
+# The initial idea was to prevent the waste of resources by not re-building the `build-tools` image
+# for the same tag in parallel workflow runs, and queue them to be skipped once we have
+# the first image pushed to Docker registry, but GitHub's concurrency mechanism is not working as expected.
+# GitHub can't have more than 1 job in a queue and removes the previous one, it causes failures if the dependent jobs.
+#
+# Ref https://github.com/orgs/community/discussions/41518
+#
+# concurrency:
+#   group: build-build-tools-image-${{ inputs.image-tag }}
+#   cancel-in-progress: false
 
 # No permission for GITHUB_TOKEN by default; the **minimal required** set of permissions should be granted in each job.
 permissions: {}