[API]: Show initial score on live scores API

[JonRay15]

Summary

The live score API below at the end of an epooch gives each team's final score for that epoch.

https://api.n00.testnet.vega.rocks/api/v2/games/team-scores?filter.gameIds=ffe85b4cc20baa4f869cf89f8a36a1f3f6eceecf1c400d6f3c11189d58a01503

But it then is not updated again until the next refresh ... which means if you uery it for the CURRENT epoch you get no info so the FE is showing "no data".

Ideally the Core would also publish a starting score for the next epoch, which obviously will be zero for everyone but would only show eligible parties. This would mean the FE could show the correct thing.