Prevent crash with WandbCallback with third parties

[tomaarsen]

What does this PR do?

This PR fixes a dodgy if-statement introduced in #30135 that attempts to check whether a model has a num_parameters method. Currently, if

(is_torch_available() and isinstance(model, torch.nn.Module))

is True, then the model does not necessarily have a num_parameters method. Instead, I've replaced it with an "Easier to ask for forgiveness than permission" principle which should be much safer.

This is currently breaking Sentence Transformers training with W&B.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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  Pull Request section?
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• Did you write any new necessary tests?

Who can review?

@amyeroberts as she reviewed #30135
@muellerz

• Tom Aarsen

[amyeroberts]

Thanks for fixing!

[amyeroberts]

Could we add a logger.info here (feel free to change the message)? By default in transformers info level isn't logged, but might be useful if someone goes into debug mode

Suggested change

	pass
	logger.info("Unable to get num_parameters from model")

[tomaarsen]

Good call, resolved via a6d09f5

[amyeroberts]

@tomaarsen Let me know if you need me to merge this in once CI is all green

[tomaarsen]

@amyeroberts I forget what the current merging protocol is for transformers. Do only the core maintainers merge?
I'm good with either way :)

• Tom Aarsen

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[amyeroberts]

@tomaarsen Once a core maintainer has approved, anyone is free to merge, I just forget who has permission to

[tomaarsen]

I see! Makes sense :) I'll merge it.

• Tom Aarsen