TrialSpawners lose SpawnData/SpawnPotentials if a BlockTransformer has been registered for the Structure placing it

Expected behavior

TrialSpawners should not lose any data in any circumstances

Observed/Actual behavior

TrialSpawners lose the SpawnData/SpawnPotentials if a BlockTransformer has been registered for a structure placing it (vanilla structures affected: Trial chambers)

Steps/models to reproduce

1. Create/Install a plugin that registers a BlockTransformer to the trial chambers structure
2. Setup and start a server and search for a trial chamber
3. Once a trial chamber is found you will see that the trial spawners have no SpanData or SpawnPotentials

Plugin and Datapack List

The test plugin that can be found in the spigot issue linked below

Paper version

Any version after the hardfork and before the hardfork since this spigot PR: https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/pull-requests/1354/overview

Other

Please checkout this issue, it shows the bug in spigot and its fix to it as it was introduced upstream before the hardfork: https://hub.spigotmc.org/jira/browse/SPIGOT-8068

Start by reviewing linked pull request #12732 and the upstream SPIGOT-8068 issue, then reproduce the problem with a BlockTransformer registered for trial chambers. Done means trial spawners retain their SpawnData and SpawnPotentials when the structure is placed.