Add ValueType.NULL

[judahrand]

Signed-off-by: Judah Rand 17158624+judahrand@users.noreply.github.com

What this PR does / why we need it:
This PR fixes this simple case:

from datetime import datetime, timedelta
from feast import Entity, Feature, FeatureStore, FeatureView, FileSource, ValueType
import numpy as np
import pandas as pd
from pathlib import Path

df = pd.DataFrame(columns=["device_type", "encoding", "datetime"])
df["device_type"] = ["A", "B", "C", "D"]
df["encoding"] = [[0, 1, 0], [1, 0, 0], None, [0, 0, 0]]
df["rank"] = np.array([1, None, 3, 4], dtype=np.float64)
df["datetime"] = pd.to_datetime([datetime.now()] * 4)
device_encodings_path_str = "data/device_encodings.parquet"
device_encodings_path = Path(device_encodings_path_str)
device_encodings_abs_path_str = str(device_encodings_path.absolute())
df.to_parquet(device_encodings_abs_path_str)
device_encodings = FileSource(
    path=device_encodings_abs_path_str, event_timestamp_column="datetime"
)
device_type = Entity("device_type", value_type=ValueType.STRING, description="")
device_encoding_view = FeatureView(
    name="device_encoding",
    entities=["device_type"],
    ttl=timedelta(minutes=60),
    input=device_encodings,
    online=True,
)
fm = FeatureStore(repo_path=".")
fm.apply([device_type, device_encoding_view])
fm.materialize(start_date=datetime(2021, 1, 1), end_date=datetime.now())

res = fm.get_online_features(
    [
        "device_encoding:encoding",
        "device_encoding:rank",
    ],
    entity_rows=df["device_type"].to_frame().to_dict("record"),
).to_df()
print(res)

(Okay, I might have sneaked quite a lot of tidy up in here too...)
Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

Fixes issues with NULL values

[codecov-commenter]

Codecov Report

Merging #1893 (48cc062) into master (7d177b6) will decrease coverage by 21.66%.
The diff coverage is 64.00%.

@@             Coverage Diff             @@
##           master    #1893       +/-   ##
===========================================
- Coverage   83.76%   62.09%   -21.67%     
===========================================
  Files          96       96               
  Lines        7424     7430        +6     
===========================================
- Hits         6219     4614     -1605     
- Misses       1205     2816     +1611     

Flag	Coverage Δ
integrationtests	?
unittests	62.09% <64.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
sdk/python/feast/infra/utils/aws_utils.py	31.25% <0.00%> (-51.79%)	⬇️
sdk/python/feast/type_map.py	51.11% <65.00%> (-31.20%)	⬇️
sdk/python/feast/online_response.py	84.90% <66.66%> (-1.89%)	⬇️
sdk/python/feast/value_type.py	75.86% <100.00%> (+0.86%)	⬆️
.../integration/online_store/test_universal_online.py	14.73% <0.00%> (-85.27%)	⬇️
.../integration/online_store/test_online_retrieval.py	17.39% <0.00%> (-82.61%)	⬇️
sdk/python/tests/utils/online_read_write_test.py	18.18% <0.00%> (-81.82%)	⬇️
...fline_store/test_universal_historical_retrieval.py	18.69% <0.00%> (-80.49%)	⬇️
...gration/registration/test_feature_service_apply.py	31.25% <0.00%> (-68.75%)	⬇️
sdk/python/tests/data/data_creator.py	34.78% <0.00%> (-65.22%)	⬇️
... and 48 more

---

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[adchia]

/lgtm

[feast-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: adchia, judahrand

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