[#83211730] Fixing TeamSnap event webhooks.

- Fixed an issue where adding a group to an existing event would not trigger the correct actions.
- Fixed an issue where multiple events would be created for a unique event, if a game was made with more than one competitor.
- Fixed an issue where the response was not being decoded correctly after sending an initial request to TeamSnap for a game event with competitors.
- Moved group check to TeamSnap webhook template and added check to each unique webhooks `process()`
- Fixed typos in comments

Requires: https://github.com/AllPlayers/allplayers-mainline/pull/4118
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