Feature names that contain double underscore are excluded from `FeatureStore.get_online_features` `OnlineResponse`

[srausser]

Expected Behavior

FeatureStore.get_online_features should return all requested features regardless of how many consecutive underscores are in the feature name.

Current Behavior

If a feature has a double underscore in it's name, it is excluded from the OnlineResponse. particular line that creates bug

Steps to reproduce

Add a feature with double underscore in its name to a feature view. Then call FeatureStore.get_online_features with that feature as one of the features and that feature will be excluded from the OnlineResponse

Specifications

• Version: 0.21.3
• Platform: macOS Big Sur/ubuntu 18
• Subsystem:

Possible Solution

1. use partition instead of rpartition when splitting feature-view:feature-name -- this will push double underscore issue from feature name to feature view name (can't have double underscore in feature view name)
2. change split key from __ to something more unique
3. raise exception during feast apply if double underscore found in a feature name