fix: ensure only canonical state is returned if requested by number/hash

[mattsse]

Closes #4515

Closes #4514

while we can also lookup the pending block by number, this breaks cross-client behaviour since only canonical state should be available if requested via block number or hash.

This removes a if num == latest + 1 check and adds more docs

[codecov]

Codecov Report

Merging #4517 (b9ec8a5) into main (82a5ffa) will increase coverage by 0.02%.
Report is 1 commits behind head on main.
The diff coverage is 0.00%.

Files Changed	Coverage Δ
crates/rpc/rpc/src/eth/api/mod.rs	61.50% <ø> (ø)
crates/storage/provider/src/providers/mod.rs	19.52% <ø> (+1.64%)	⬆️
crates/storage/provider/src/traits/state.rs	27.11% <0.00%> (-0.96%)	⬇️

... and 9 files with indirect coverage changes

Flag	Coverage Δ
integration-tests	16.73% <0.00%> (+<0.01%)	⬆️
unit-tests	63.91% <0.00%> (+0.01%)	⬆️

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

Components	Coverage Δ
reth binary	29.71% <ø> (ø)
blockchain tree	83.58% <ø> (ø)
pipeline	90.56% <ø> (ø)
storage (db)	75.33% <0.00%> (+0.26%)	⬆️
trie	94.84% <ø> (-0.04%)	⬇️
txpool	47.47% <ø> (ø)
networking	77.48% <ø> (+0.01%)	⬆️
rpc	57.44% <ø> (-0.01%)	⬇️
consensus	63.32% <ø> (-0.09%)	⬇️
revm	31.74% <ø> (ø)
payload builder	6.34% <ø> (ø)
primitives	86.48% <ø> (-0.03%)	⬇️

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[Rjected]

I see, this makes sense for compatibility / conformance