fix(rpc): remove invalid block hash variant

[mattsse]

Closes #2947

this variant is deprecated with v2 and can also be removed from V1

ethereum/go-ethereum#26696

geth also no longer has it

https://github.com/ethereum/go-ethereum/blob/73697529994e14996b7740730481e926d5ec3e40/beacon/engine/errors.go#L61-L61

[codecov-commenter]

Codecov Report

Merging #2954 (78983f4) into main (43f421d) will increase coverage by 0.04%.
The diff coverage is 100.00%.

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@@            Coverage Diff             @@
##             main    #2954      +/-   ##
==========================================
+ Coverage   71.05%   71.10%   +0.04%     
==========================================
  Files         517      517              
  Lines       67056    67049       -7     
==========================================
+ Hits        47646    47672      +26     
+ Misses      19410    19377      -33     

Flag	Coverage Δ
integration-tests	17.30% <0.00%> (+<0.01%)	⬆️
unit-tests	66.00% <100.00%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
crates/consensus/beacon/src/engine/forkchoice.rs	79.06% <ø> (+1.79%)	⬆️
crates/rpc/rpc-types/src/eth/engine/payload.rs	87.30% <100.00%> (+2.82%)	⬆️

... and 14 files with indirect coverage changes

[rkrasiuk]

lgtm