Clarify which servers on test networks are full history

[julian78780]

We mention which servers are full history under Mainnet here: https://xrpl.org/docs/tutorials/public-servers

but nothing regarding test networks. We had a partner recently reach out saying that they were struggling with testnet connections with a full history node for indexing purposes. Can we please clarify which ones are full history.

Thanks

[mDuo13]

I'm not aware of any test network servers that promise to be full history.