[MLPerf 6.1][GRPO] Update Qwen3.5 reference assets

[jepio]

Summary

During dataset publishing to MLCommons storage we identified entries that had different behavior between architectures or were fundamentally broken. The result is that the number of datasets in the training and validation set slightly changed, without impacting convergence behavior of the benchmark.

We are also proposing a change to the reference configuration to reduce command and test timeouts from 300/180 to 60/60. These don't affect correctness/convergence but prevent training stalls and allow for better submissions.

Detailed changes in this PR are:

• Documents MLCommons storage as the primary source for the qualified Qwen3.5 checkpoint, dataset, and SIF images.
• Keeps the source preparation and build instructions as optional alternatives.
• Updates the qualified dataset identities, task counts, runtime settings, and NeMo-RL submodule revision.
• Links the NeMo-RL updated mlperf-training-qwen35-main branch.

Related compliance checker update:

• Update Qwen3.5 validation sample count logging#475.

[github-actions]

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[RissyRan]

Thanks for the change and proposal! Have 2 questions:

1. Similar one about 251 samples in validation in Update Qwen3.5 validation sample count logging#475
2. What're are actual train and validation test/command timeout in reference runs?

[ShriyaRishab]

@jepio can you please answer the open questions and add some stats?

[jepio]

@ShriyaRishab

1. i answered the 251 validation sample question here: Update Qwen3.5 validation sample count logging#475 (comment)
2. before this PR the reference uses:

train test time	300s
validation test time	180s
train command timeout	300s
validation command timeout	300s