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