ci: l4lb: gather more infos about docker-in-docker issues

[mhofstetter]

Sometimes, the L4LB tests timeout waiting for the docker (in docker) instance to get ready.

+[06:55:18] docker run --privileged --name lb-node -d --network cilium-l4lb -v /lib/modules:/lib/modules docker:dind
ca31f2a72a098bf612d569fee976e7e17779a1546337748dc62b63c99da13271
+[06:55:18] docker exec -t lb-node mount bpffs /sys/fs/bpf -t bpf
+[06:55:18] docker run --name nginx -d --network cilium-l4lb nginx
544abbd0503584c582da50480d5f96eae5ecadb426d48d6fee078558b45451b2
+[06:55:18] docker exec -t lb-node docker ps
+[06:55:18] sleep 1
+[06:55:19] docker exec -t lb-node docker ps
+[06:55:19] sleep 1
+[06:55:20] docker exec -t lb-node docker ps
Error response from daemon: Container ca31f2a72a098bf612d569fee976e7e17779a1546337748dc62b63c99da13271 is not running
+[06:55:20] sleep 1
+[06:55:21] docker exec -t lb-node docker ps
Error response from daemon: Container ca31f2a72a098bf612d569fee976e7e17779a1546337748dc62b63c99da13271 is not running
+[06:55:21] sleep 1
+[06:55:22] docker exec -t lb-node docker ps
Error response from daemon: Container ca31f2a72a098bf612d569fee976e7e17779a1546337748dc62b63c99da13271 is not running
+[06:55:22] sleep 1
+[06:55:23] docker exec -t lb-node docker ps
Error response from daemon: Container ca31f2a72a098bf612d569fee976e7e17779a1546337748dc62b63c99da13271 is not running
+[06:55:20] docker exec -t lb-node docker ps
Error response from daemon: Container ca31f2a72a098bf612d569fee976e7e17779a1546337748dc62b63c99da13271 is not running

Unfortunately, fetching the LB logs after the failed test doesn't help either, as this fails with the same error.

Run docker exec -t lb-node docker logs cilium-lb
  docker exec -t lb-node docker logs cilium-lb
...
Error response from daemon: Container ca31f2a72a098bf612d569fee976e7e17779a1546337748dc62b63c99da13271 is not running

Therefore, this commit adds an additional job step that fetches the status and logs of the docker instance itself.

Examples:

• https://github.com/cilium/cilium/actions/runs/9053573212/job/24872468158
• https://github.com/cilium/cilium/actions/runs/9067978554/job/24914256383
• https://github.com/cilium/cilium/actions/runs/9074981805/job/24934711124
• https://github.com/cilium/cilium/actions/runs/9083769577/job/24963174702

[mhofstetter]

/test