Description

DRAFT PR: should fix the issue, but waiting for event to occur again to verify

Small fix to fix to resolve TypeError for all hype train events. If not a shared train, return empty list for shared_train_participants.
Problem in BaseHypeTrain causes the same error for hype train begin, progress and end due to 'shared_train_participants' in event being None.

File "/twitchio/models/eventsub_.py", line 4960, in __init__
    self.shared_train_participants: list[PartialUser] = [
                                                        ^
TypeError: 'NoneType' object is not iterable

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
  • I have updated the changelog with a quick recap of my changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)
• I have read and agree to the Developer Certificate of Origin for this contribution