feat(participantTable): merge instead of skip for `duplicate` placements

[hjpalpha]

Summary

Currently ParticipantTable skips storage for entries that already have a placement on the page. This PR changes this behaviour into merging the data from ParticipantTable into the one of the Placement it finds.

This PR is needed for another follow up PR for RLs Player/Ext/Custom

How did you test this change?

dev