rm unused engine_exchangeTransitionConfigurationV1 calling signature

[tersec]

engine_exchangeTransitionConfigurationV1 MUST not be used anymore by clients, and nimbus-eth2 does not use it as of status-im/nimbus-eth2#5889, so remove it.

nimbus-eth1 can still choose to support it (though, must not require it for Dencun-scheduled networks), so leaving TransitionConfigurationV1 in place. The removed signature is for client-side calling only, and does not affect nimbus-eth1.

https://github.com/ethereum/execution-apis/blob/a0d03086564ab1838b462befbc083f873dcf0c0f/src/engine/cancun.md#deprecate-engine_exchangetransitionconfigurationv1 says:

This document introduces deprecation of engine_exchangeTransitionConfigurationV1. The deprecation is specified as follows:

1. Consensus layer clients MUST NOT call this method.

2. Execution layer clients MUST NOT surface an error message to the user if this method is not called.

[tersec]

https://github.com/status-im/nimbus-eth1/blob/966adcb1245d814a26fd5f082c4e5ca01bb1fce9/hive_integration/nodocker/engine/auths_tests.nim#L65-L75 does appear to use the client version, so, won't merge.

It's not clear if it's used for any specific reason or whether it's a stand-in for just a relatively innocuous message to send to an EL to check the JWT auth. If the latter, a bit unfortunate to pin a client RPC call signature which specs require not to be used, as just some arbitrary call, if an alternative exists.

[arnetheduck]

needs merge