chore: return empty vec if input vec is empty

[mattsse]

no need to aquire a readlock here

[codecov]

Codecov Report

Merging #4906 (0c97f77) into main (5f56e52) will decrease coverage by 0.04%.
Report is 1 commits behind head on main.
The diff coverage is 33.33%.

Files	Coverage Δ
crates/transaction-pool/src/pool/mod.rs	50.35% <33.33%> (-0.19%)	⬇️

... and 10 files with indirect coverage changes

Flag	Coverage Δ
integration-tests	15.50% <0.00%> (-0.01%)	⬇️
unit-tests	62.65% <33.33%> (-0.04%)	⬇️

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

Components	Coverage Δ
reth binary	32.58% <ø> (ø)
blockchain tree	80.64% <ø> (ø)
pipeline	88.45% <ø> (ø)
storage (db)	73.32% <ø> (ø)
trie	94.48% <ø> (-0.04%)	⬇️
txpool	49.10% <33.33%> (-0.49%)	⬇️
networking	76.09% <ø> (-0.03%)	⬇️
rpc	57.72% <ø> (ø)
consensus	61.05% <ø> (ø)
revm	28.47% <ø> (ø)
payload builder	8.16% <ø> (ø)
primitives	85.43% <ø> (+0.01%)	⬆️