Remove upper bound for fsspec

### Describe the bug

As also raised by @cyyever in https://github.com/huggingface/datasets/pull/7296 and @NeilGirdhar in https://github.com/huggingface/datasets/commit/d5468836fe94e8be1ae093397dd43d4a2503b926#commitcomment-140952162 , `datasets` has a problematic version constraint on `fsspec`.

In our case this causes (unnecessary?) troubles due to a race condition bug in that version of the corresponding `gcsfs` plugin, that causes deadlocks: https://github.com/fsspec/gcsfs/pull/643

We just use a version override to ignore the constraint from `datasets`, but imho the version constraint could just be removed in the first place?

The last few PRs bumping the upper bound were basically uneventful:

* https://github.com/huggingface/datasets/pull/7219
* https://github.com/huggingface/datasets/pull/6921
* https://github.com/huggingface/datasets/pull/6747

### Steps to reproduce the bug

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### Expected behavior

Installing `fsspec>=2024.10.0` along `datasets` should be possible without overwriting constraints.

### Environment info

All recent datasets versions