lint: fix warnings

[cce]

Summary

@algojack got the warning-level linters working again in #5006 which missed a few warnings while it was broken. This fixes those warnings.

Test Plan

Tests should pass, and warning-level linter output should be empty now.

[algojack]

lgtm

[codecov]

Codecov Report

Merging #5047 (9470ca2) into master (7e37e00) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #5047   +/-   ##
=======================================
  Coverage   53.48%   53.48%           
=======================================
  Files         429      429           
  Lines       54043    54033   -10     
=======================================
- Hits        28904    28899    -5     
+ Misses      22894    22887    -7     
- Partials     2245     2247    +2     

Impacted Files	Coverage Δ
cmd/tealdbg/dryrunRequest.go	65.90% <ø> (+12.20%)	⬆️
shared/pingpong/pingpong.go	0.00% <ø> (ø)
util/rateLimit.go	82.35% <ø> (ø)
util/tcpinfo_linux.go	0.00% <ø> (ø)
crypto/merkletrie/trie.go	66.42% <0.00%> (-2.19%)	⬇️
crypto/merkletrie/node.go	91.62% <0.00%> (-1.87%)	⬇️
ledger/acctupdates.go	68.75% <0.00%> (-0.73%)	⬇️
ledger/testing/randomAccounts.go	56.26% <0.00%> (-0.62%)	⬇️
network/wsNetwork.go	64.92% <0.00%> (ø)
catchup/service.go	69.80% <0.00%> (+0.72%)	⬆️
... and 2 more

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