fix: add keras extension in the file path of integ test

[pintaoz-aws]

Issue #, if available:

Description of changes:
There is a recent update from keras 3.5.0, which adds a check to its save model method that requires a file extension with .keras or .h5. This PR is fixing the integration test by adding .keras in the file path.
Testing done:

Merge Checklist

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• I have read the CONTRIBUTING doc
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Tests

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