Fix Daily CI reporting issues
Author: tarekziade
Pull request: yes

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# What this PR does

## Fix 1

The scheduled model CI collated report can fail before uploading reports with:

```
collated_reports.py: error: argument --machine-type/-m: expected one argument
```

`.github/workflows/model_jobs.yml` was passing `machine_type` to the reusable collated report workflow from `needs.run_models_gpu.outputs.machine_type`. 

That job is matrixed, so relying on a matrix job output here can produce an empty value for the downstream reusable workflow.

This moves the normalized report machine type into a small non-matrix `report_metadata` job and passes `needs.report_metadata.outputs.machine_type` to `collated-reports.yml`. The per-matrix test job still sets `machine_type` in `GITHUB_ENV` for artifact names exactly as before.

## Fix 2

The generated folder matrix crossed GitHub’s 256-job limit:

- July 15: 512 dirs -> [256, 256]
- July 16: 514 dirs -> [257, 257]

Added a slice

## Fix 3

  Some model CI jobs can upload a partial report artifact without summary_short.txt when pytest does
  not reach its terminal summary hook. The collated report job then fails with:

  FileNotFoundError: [Errno 2] No such file or directory:
    '<artifact>/summary_short.txt'

  This makes utils/collated_reports.py tolerate missing summary_short.txt files. Instead of crashing
  the entire collated report job, it records that artifact as an error entry and continues processing
  the remaining reports.

  This preserves the useful collated report output while still surfacing the malformed/incomplete
  artifact as a failure signal.

Comments:
Triggered a new daily https://github.com/huggingface/transformers/actions/runs/29483227997

The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_47364). All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

> Thanks, do you know why this happened all of a sudden? It only started failing a few days ago it seems

the July 13 issues are yet another issue I am looking at


Checked run 29502875190:

  https://github.com/huggingface/transformers/actions/runs/29502875190

  Result: failed, but the reporting fix path worked.

  Key signal:

  All 4 Model CI / Collated Reports jobs succeeded

  Those are:

  87641539498 single-gpu slice 0
  87642640285 single-gpu slice 1
  87643694669 multi-gpu slice 0
  87644784416 multi-gpu slice 1

  So #47364’s machine-type/matrix fix is doing what we wanted here: matrix jobs materialized,
  machine_type was not empty, and collated reports completed.

  The run is red because model jobs failed:

  llama     single + multi
  wav2vec2  single + multi
  whisper   single + multi
  blip      multi

  Examples:

  - llama: generation assertion mismatch in test_llama_3_1_hard
  - wav2vec2: ONNXRuntime Expand node broadcast failure
  - whisper: many integration failures, including float vs half conv mismatch
  - blip: model parallelism device mismatch, cuda:0 vs cuda:1

  No summary_short.txt / created_at / empty machine_type failure in the collated report jobs on this
  run.

run-slow: whisper, wav2vec2, llama

[Workflow Run ⚙️](https://github.com/huggingface/transformers/actions/runs/29512032809)

This comment contains `run-slow`, running the specified jobs: 

models: ["models/llama", "models/wav2vec2", "models/whisper"]
quantizations: []

new run with the 3 fixes https://github.com/huggingface/transformers/actions/runs/29512139671

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---

### CI recap

**Dashboard:** [View test results in Grafana](https://transformers-ci.lor-e.huggingface.cool/d/pytest-observability-by-pr/pytest-observability-branch?var-pr=47364)
**Latest run:** [29511760410:1](https://github.com/huggingface/transformers/actions/runs/29512001084)
**Result:** `success` | **Jobs:** 2 | **Tests:** 13 | **Failures:** 0 | **Duration:** 44s

<!-- ci-dashboard-recap:end -->

## CI Results
[Workflow Run ⚙️](https://github.com/huggingface/transformers/actions/runs/29512032809)

### Commit Info
| Context | Commit | Description |
|---------|--------|-------------|
| RUN | [3592959d](https://github.com/huggingface/transformers/commit/3592959d9cd6705bdc795c7e069d1fabe49edaaa) | workflow commit (merge commit) |
| PR | [82618664](https://github.com/huggingface/transformers/commit/8261866405209efbd424b1078d6c327d5248eb08) | branch commit (from PR) |
| main | [0f33294a](https://github.com/huggingface/transformers/commit/0f33294af580c29cdc79571663c2545cea6e9f34) | base commit (on `main`) |

✅ No failing test specific to this PR 🎉 👏 !