Migrated AdaIN tutorial to keras 3

[kharshith-k]

Please find my PR for migrating AdaIN tutorial from keras2 to keras3
Colab Gist

[gemini-code-assist]

Code Review

This pull request migrates the AdaIN style transfer example to Keras 3, replacing the tf.data pipeline with a custom keras.utils.PyDataset and removing the tensorflow_datasets dependency. The NeuralStyleTransfer model has been refactored to use compute_loss instead of a custom train_step, and TensorFlow-specific operations have been replaced with keras.ops for backend neutrality. Additionally, the PR introduces a fallback mechanism to generate local data from CIFAR-10 if the expected image directories are missing. I have no feedback to provide.