Handle np.bool to JSON NumpyEncoder

[abidwael]

Fix for the following failure
RuntimeError: Caught exception during model preprocessing: Object of type bool_ is not JSON serializable
with the following config

{'defaults': {'binary': {'preprocessing': {'missing_value_strategy': 'fill_with_mode'}}},
 'input_features': [{'name': 'binary_1', 'type': 'binary'}],
 'model_type': 'ecd',
 'output_features': [{'decoder': {'idx2str': ['lwrVkpk',
                                              'ztHj',
                                              'dQxBJ',
                                              'mLFhKPHrTn',
                                              'iBjnr',
                                              'Pb',
                                              'qyiL',
                                              'VEQv',
                                              'zLol',
                                              'SBpN'],
                                  'vocab_size': 10},
                      'name': 'category_output_1',
                      'type': 'category'}],
 'trainer': {'train_steps': 1}}

The np.bool_ exists in training_set_metadata after the data has been preprocessed and is being cached.

[github-actions]

Unit Test Results

  6 files  ±0    6 suites  ±0   22m 49s ⏱️ + 2m 23s
12 tests ±0  10 ✔️ ±0    2 💤 ±0  0 ❌ ±0 
60 runs  ±0  48 ✔️ ±0  12 💤 ±0  0 ❌ ±0 

Results for commit 1611db9. ± Comparison against base commit 7d959f7.

♻️ This comment has been updated with latest results.

[arnavgarg1]

@abidwael happy to approve, but can you update the PR description to clearly indicate when objects of type bool_ are created? It's not apparent from the config itself since the inference likely comes from the data right?

[arnavgarg1]

Ideally would be great if you can also add a small unit test!