Use logging.warning instead of warnings.warn in pipeline.__call__

[tokestermw]

What does this PR do?

Use HF logging instead of warnings.warn for the following warning:

You seem to be using the pipelines sequentially on GPU. In order to maximize efficiency please use a dataset

When using HF pipeline for inference, this warning is shown a lot, and logging can get expensive. Moving to HF logging, then we can control using transformers.logging.set_loglevel instead of the warnings package which applies to all libraries using the warnings package.

There is a heuristic here #26527. Not quite sure if this applies in this case.

What does that mean for developers of the library? We should respect the following heuristic:
 - `warnings` should be favored for developers of the library and libraries dependent on `transformers`
 - `logging` should be used for end-users of the library using it in every-day projects

Maybe another solution is to warn just once.

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• Did you write any new necessary tests?

Who can review?

@LysandreJik

[amyeroberts]

Thanks for adding this! Looks OK to me - suggestion to use warning_once instead

[amyeroberts]

I'd recommend using warning_once here. This way, the warning will only display the first time it's hit, so shouldn't spam the logs. This will hopefully discourage having to change the logging level to get it to disappear (who knows what other useful warnings you might be surpressing! :D )

Suggested change

	logger.warning(
	logger.warning_once(