Expose get_feature_names on OneHotEncoder

[angela97lin]

Closes #1183

Questions:

• scikit-learn only allows ohe.get_feature_names(input_features) to be called on the entire data set (https://github.com/scikit-learn/scikit-learn/blob/0fb307bf3/sklearn/preprocessing/_encoders.py#L580). Do we want to loosen this restriction? Unclear since I'm not sure exactly what context this will be used in. For now, could be sufficient to just follow impl and add as a later PR if the need arises.

[codecov]

Codecov Report

Merging #1193 into main will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1193   +/-   ##
=======================================
  Coverage   99.92%   99.92%           
=======================================
  Files         196      196           
  Lines       11978    11987    +9     
=======================================
+ Hits        11969    11978    +9     
  Misses          9        9           

Impacted Files	Coverage Δ
...components/transformers/encoders/onehot_encoder.py	100.00% <100.00%> (ø)
...alml/tests/component_tests/test_one_hot_encoder.py	100.00% <100.00%> (ø)

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[dsherry]

@angela97lin looks great!

I wonder if we'll eventually want to adapt get_feature_names to be defined in Transformer. So that we can access the names of features generated by any component.

[angela97lin]

@dsherry Yeah, I could see something like that for the Transformer method too in the future. We already have input_feature_names on the pipelines, and getting the output could also be useful.