feat: add Validator::on_new_head_block

[mattsse]

closes #4244

this allows updating values that depend on the current height, like enabling fork based on timestamp or fees like in op-reth

cc @refcell

[codecov]

Codecov Report

Merging #4303 (2f6c8e1) into main (34b68de) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

Files Changed	Coverage Δ
crates/transaction-pool/src/lib.rs	37.91% <0.00%> (ø)
crates/transaction-pool/src/maintain.rs	3.17% <0.00%> (+0.06%)	⬆️
crates/transaction-pool/src/pool/mod.rs	44.91% <0.00%> (+0.78%)	⬆️
crates/transaction-pool/src/traits.rs	7.38% <0.00%> (-0.64%)	⬇️
crates/transaction-pool/src/validate/mod.rs	55.10% <0.00%> (-0.57%)	⬇️

... and 8 files with indirect coverage changes

Flag	Coverage Δ
integration-tests	16.83% <0.00%> (+<0.01%)	⬆️
unit-tests	63.76% <0.00%> (-0.01%)	⬇️

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

Components	Coverage Δ
reth binary	26.12% <ø> (ø)
blockchain tree	82.56% <ø> (ø)
pipeline	90.07% <ø> (ø)
storage (db)	74.77% <ø> (ø)
trie	94.85% <ø> (+0.03%)	⬆️
txpool	48.20% <0.00%> (-0.03%)	⬇️
networking	77.53% <ø> (-0.02%)	⬇️
rpc	58.81% <ø> (-0.01%)	⬇️
consensus	63.53% <ø> (ø)
revm	32.01% <ø> (ø)
payload builder	6.82% <ø> (ø)
primitives	86.16% <ø> (+0.01%)	⬆️

[Rjected]

makes sense to have a block ref here