Revert docker.sock path to /var/run/docker.sock (#2536)

Starting ARC v0.27.2, we've changed the `docker.sock` path from `/var/run/docker.sock` to `/var/run/docker/docker.sock`. That resulted in breaking some container-based actions due to the hard-coded `docker.sock` path in various places.

Even `actions/runner` seem to use `/var/run/docker.sock` for building container-based actions and for service containers?

Anyway, this fixes that by moving the sock file back to the previous location.

Once this gets merged, users stuck at ARC v0.27.1, previously upgraded to 0.27.2 or 0.27.3 and reverted back to v0.27.1 due to #2519, should be able to upgrade to the upcoming v0.27.4.

Resolves #2519
Resolves #2538

acceptance/deploy.sh

@@ -102,6 +102,7 @@ if [ "${tool}" == "helm" ]; then
     --set githubWebhookServer.podAnnotations.test-id=${TEST_ID} \
     --set actionsMetricsServer.podAnnotations.test-id=${TEST_ID} \
     ${flags[@]} --set image.imagePullPolicy=${IMAGE_PULL_POLICY} \
+    --set image.dindSidecarRepositoryAndTag=${DIND_SIDECAR_REPOSITORY_AND_TAG} \
     -f ${VALUES_FILE}
   set +v
   # To prevent `CustomResourceDefinition.apiextensions.k8s.io "runners.actions.summerwind.dev" is invalid: metadata.annotations: Too long: must have at most 262144 bytes`