Default mapped entity data not respected in <1.19.3 #1361

'/viaversion dump' Output

https://dump.viaversion.com/109a0d101747918a786b652368bf5f5642f12e30fe02b2b63edd95e7731ff8ba

Server/Client Error

No response

Bug Description

When remapping an entity type with mapEntityTypeWithData and specifying default entity data with spawnEntityData, that specified data is only sent when the first entity data packet arrives for the entity.

However, in 1.19.3+, entity data that's unchanged from the defaults is no longer sent (see also #1315), and if no data is available as a result of this, the packet is skipped altogether.

Steps to Reproduce

I found it easy to see with interaction entities.

1. Summon an interaction with default values: /summon interaction ~ ~ ~
2. Any connected <1.19.3 client will receive an invisible armor stand, because all entity data is sent on first spawn (which checks out with the painting PR linked above)
3. Relog with the <1.19.3 client
4. Interaction now appears as a fully visible, big armor stand

As soon as you change any of the interaction's default values, this stops occurring because the entity data is sent on track.

Additional Server Info

No response

Checklist

• Via plugins are only running on EITHER the backend servers (e.g. Paper) OR the proxy (e.g. Velocity), not on both.
• I have included a ViaVersion dump.
• If applicable, I have included a paste (not a screenshot) of the error.
• I have tried a build from https://ci.viaversion.com/ and the issue still persists.