remove RpcNodeCoreExt trait

[mattsse]

Describe the feature

this trait is a bit problematic for #17054

and should be changed so that this is more like

reth/crates/rpc/rpc-eth-api/src/helpers/blocking_task.rs

Line 15 in 162568b

pub trait SpawnBlocking: EthApiTypes + Clone + Send + Sync + 'static {

which already provides access to internals

Additional context

No response