Incorrect return value for channel.prediction.lock

[Xemdo]

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Problem/Feature

Fixes #241

Description of Changes:

• Fixed channel_points_won field to now show null on channel.prediction.progress and channel.prediction.lock

Checklist

• My code follows the Contribution Guide
• I have self-reviewed the changes being requested
• I have made comments on pieces of code that may be difficult to understand for other editors
• I have updated the documentation (if applicable)