feat(testnet): introduce new API version for testnet to handle Trie error from 2412?

[peterwht]

#425 (comment)

In the 2412 uplift, a new variant in DispatchError was introduced: Trie. If we want to maintain backwards compatibly for testnet, we would have to create a new API version for the DispatchError that uses Trie, and then a mapping to the UnknownVariant to ensure things stay backwards compatible for the old API version.

[Daanvdplas]

I think we should value this change in the SDK and take it as an exercise for how to handle these breaking changes for contracts deployed. We don't know how often this might happen so we want to extract all the information from it that is possible.