Bump minimum torch version to 2.5 and clean up torch<2.5 workarounds
Author: cyyever
Pull request: yes

# What does this PR do?

Bump min torch to 2.5 and remove workarounds.

## Code Agent Policy


- [x] I confirm that this is not a pure code agent PR.

## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [ ] Did you read the [contributor guideline](https://huggingface.co/docs/transformers/contributing) and the
      [Pull Request](https://huggingface.co/docs/transformers/pr_checks) checks?
- [ ] Was this discussed/approved via a Github issue or the [forum](https://discuss.huggingface.co/)? Please add a link
      to it if that's the case.
- [ ] Did you make sure to update the documentation with your changes according to the [guidelines](https://github.com/huggingface/transformers/tree/main/docs)?
- [ ] Did you write any new necessary [tests](https://huggingface.co/docs/transformers/testing)?


## Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

<!-- Your PR will be replied to more quickly if you can figure out the right person to tag with @

 If you know how to use git blame, that is the easiest way, otherwise, here is a rough guide of **who to tag**.
 Please tag fewer than 3 people.

Models:

- text models: @ArthurZucker @Cyrilvallez @vasqu
- vision models: @yonigozlan @molbap
- audio models: @eustlb @ebezzam @vasqu
- multimodal models: @zucchini-nlp
- graph models: @clefourrier

Library:

- generate: @zucchini-nlp (visual-language models) or @Cyrilvallez (all others)
- continuous batching: @remi-or @ArthurZucker @McPatate
- pipelines: @Rocketknight1
- tokenizers: @ArthurZucker and @itazap
- trainer: @SunMarc
- attention: @vasqu @ArthurZucker @CyrilVallez
- model loading (from pretrained, etc): @CyrilVallez
- distributed: @3outeille @ArthurZucker
- CIs: @ydshieh

Integrations:

- ray/raytune: @richardliaw, @amogkam
- Big Model Inference: @SunMarc
- quantization: @SunMarc
- kernels: @vasqu @drbh
- peft: @BenjaminBossan @githubnemo

Devices/Backends:

- AMD ROCm: @ivarflakstad
- Intel XPU: @IlyasMoutawwakil
- Ascend NPU: @ivarflakstad 

Documentation: @stevhliu

Research projects are not maintained and should be taken as is.

 -->


Comments:
Thank you for your contribution 🤗!

## CI Security Gate — automatic approval blocked

This PR was **not** automatically approved for CI because the security gate failed.

**Possible reasons:**
- The PR touches 50 or more files — only PRs with fewer than 50 changed files are automatically approved
- A changed file is outside the allowed directories (`src/`, `tests/`, `docs/`, `utils/`), has a disallowed extension (only `.py`, `.txt`, `.md` permitted outside `tests/` and `docs/`), or is not `.md`/`.yml` inside `docs/`
- A new high-severity security issue was detected in the changed Python files (Bandit check)

See the [workflow run](https://github.com/huggingface/transformers/actions/runs/28285038932) for the exact violations.

A maintainer can review and manually approve CI if a finding is a false positive.

**[For maintainers]** Suggested jobs to run (before merge)

run-slow: cohere2, gemma2, vaultgemma

Wait, where did we decide to do this version bump?

Not decided, it is an experimental PR to test what files to change.