[Speech2Text] Give feature extraction higher tolerance
Author: patrickvonplaten
Pull request: yes

# What does this PR do?

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Fixes flaky test: tests/test_feature_extraction_speech_to_text.py::Speech2TextFeatureExtractionTest::test_cepstral_mean_and_variance_normalization_np

@patil-suraj @anton-l - I looked quite a bit into it and IMO it's not a bug in the computation, but due to differences in casting "pure python" to "numpy". 


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Models:

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Comments:
Merging this for now to keep the CI green - ran the test in loop 50 times locally without failure.