Add Jupyter Notebook Format Check to format_check.sh

[Aniketsy]

#681
This PR adds a check to format_check.sh to ensure all Jupyter Notebook (.ipynb) files are in the correct format before merging. The script now uses nbstripout --check to verify that notebooks do not contain unwanted outputs or metadata.

Please let me know if this fix needs any improvements . I’m open to feedback and happy to make changes based on suggestions.
Thankyou!

[Aniketsy]

@mhucka Please review these changes when you have a chance.

[Aniketsy]

======================================================================
FAIL: test_3_qubit_circuit (__main__.SPSAMinimizerTest)
SPSAMinimizerTest.test_3_qubit_circuit
Test quantum circuit optimization, adapted from Qiskit SPSA testing
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/.cache/bazel/_bazel_runner/865e0ada367db183bc26de9a3083631f/execroot/__main__/bazel-out/k8-opt/bin/tensorflow_quantum/python/optimizers/spsa_minimizer_test.runfiles/__main__/tensorflow_quantum/python/optimizers/spsa_minimizer_test.py", line 219, in test_3_qubit_circuit
    self.assertLess(result.objective_value.numpy(), -0.95)
AssertionError: -0.8339844 not less than -0.95

I dont think this CI check fail related to these changes , please correct me if i am wrong also i'm getting same check fail in other #903

[mhucka]

Thanks for this. I think it will be better to take this in a different direction, and use nbformat rather than introduce a new dependency (nbstripout). The former is already being used in TFQ. nbformat has validation facilities.

@Aniketsy Let us know if you would like to update this PR accordingly. No worries if you do not have the time or are not interested in pursuing it.

[Aniketsy]

@mhucka Thanks for the feedback. I’ll update the code with the suggested changes.