fix: integrate PR #3396 review feedback (round 2)

- envs(vlabench): drop the unused `episode_index` / `n_envs`
  constructor args — they were stored but never referenced.
- envs(vlabench): replace module-level `print()` calls with the
  standard `logging.getLogger(__name__)` logger (matches the rest
  of the repo's script convention). Covers the two PhysicsError
  retry/step paths and the `create_vlabench_envs` progress lines.
- envs(vlabench): drop `_make_env_fns` and build factories
  MetaWorld-style via a lambda list comprehension — simpler, no
  extra helper.
- docker(vlabench): pin upstream clones to commit SHAs
  (`OpenMOSS/VLABench@cf588fe6`, `motion-planning/rrt-algorithms@e51d95ee`)
  so benchmark images are reproducible.
- ci(vlabench): run `scripts/ci/extract_task_descriptions.py` after
  the eval so `metrics.json` carries per-task natural-language
  labels, matching LIBERO / MetaWorld jobs. Added a VLABench
  extractor that produces cleaned-name labels keyed by `<task>_0`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/benchmark_tests.yml

@@ -379,6 +379,10 @@ jobs:
                 --policy.device=cuda \
                 '--rename_map={\"observation.images.image\": \"observation.images.camera1\", \"observation.images.second_image\": \"observation.images.camera2\", \"observation.images.wrist_image\": \"observation.images.camera3\"}' \
                 --output_dir=/tmp/eval-artifacts
+              python scripts/ci/extract_task_descriptions.py \
+                --env vlabench \
+                --task select_fruit,select_toy,select_book,select_painting,select_drink,select_ingredient,select_billiards,select_poker,add_condiment,insert_flower \
+                --output /tmp/eval-artifacts/task_descriptions.json
             "
 
       - name: Copy VLABench artifacts from container