Remove old name Thrower data for converted item entities

[chickeneer]

Related Mojira issue created (reproduced separately): https://report.bugs.mojang.com/servicedesk/customer/portal/2/MC-305352

Running a paper server. An item dropped on the ground from before 1.13 (so say 1.12.2). When loaded the following error is logged into the console.

chunk@[-1488, 1166]:
  [1]: Failed to decode value '"ellisbrewer"' from field 'Thrower': Not a list

Item entities used to store the Thrower as a player name. Then on the 1.12 -> 1.13 update, they started storing as UUID L/M version. Though, searching the code, I cannot find a datafixer that dropped the old data.
https://minecraft.wiki/w/Java_Edition_1.13#:~:text=in%20each%20compound.-,thrower,-and

Then in the 1.15.2 -> 1.16 update. They convert the UUID L/M to the array of 4 Ints. (Data converter 2514)
https://minecraft.wiki/w/Java_Edition_1.16#:~:text=now%20much%20darker.-,uuids,-UUIDs%20stored%20in

Hence the issue of being Not a List. By my best figuring. The issue is that the EntityUUIDFix/V2514 is passing on the original name String, instead of removing it completely when it can't convert it to a modern UUID.

The solution proposed is to always remove the old data, regardless of whether a not null uuid was found. Reason it isn't already, is probably due to that data being lost. But the consequence is this error...

[Spottedleaf]

This looks correct to me, although I do want to wait a bit and see how Mojang responds.