chore: use DEFAULT_DISCOVERY_PORT constant

[PatStiles]

Closes #4274 . Reopened #4275 due to rebase issues.

[codecov]

Codecov Report

Merging #4356 (716ef2c) into main (50ba828) will decrease coverage by 51.68%.
The diff coverage is 23.07%.

Files Changed	Coverage Δ
crates/net/discv4/src/lib.rs	15.39% <0.00%> (-49.43%)	⬇️
crates/net/discv4/src/proto.rs	0.00% <0.00%> (-92.64%)	⬇️
crates/net/eth-wire/src/ethstream.rs	22.30% <0.00%> (-61.88%)	⬇️
crates/net/eth-wire/src/p2pstream.rs	50.59% <0.00%> (-29.72%)	⬇️
crates/net/eth-wire/src/hello.rs	22.58% <25.00%> (-60.22%)	⬇️
crates/net/eth-wire/src/builder.rs	68.75% <100.00%> (ø)
crates/net/network-api/src/noop.rs	76.92% <100.00%> (ø)

... and 374 files with indirect coverage changes

Flag	Coverage Δ
integration-tests	16.70% <23.07%> (-0.01%)	⬇️
unit-tests	?

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

Components	Coverage Δ
reth binary	6.77% <ø> (-19.25%)	⬇️
blockchain tree	0.00% <ø> (-82.57%)	⬇️
pipeline	0.00% <ø> (-90.08%)	⬇️
storage (db)	17.67% <ø> (-57.06%)	⬇️
trie	0.00% <ø> (-94.89%)	⬇️
txpool	21.63% <ø> (-25.60%)	⬇️
networking	27.12% <23.07%> (-50.36%)	⬇️
rpc	25.82% <ø> (-32.16%)	⬇️
consensus	0.98% <ø> (-62.55%)	⬇️
revm	1.37% <ø> (-30.53%)	⬇️
payload builder	6.78% <ø> (ø)
primitives	22.24% <ø> (-64.06%)	⬇️