chore: fix issues reported by `go vet` #5266

Job	Run time
setup	6s
Run Main (gnofaucet) / Go Linter / lint	32s
Run Main (gnodev) / Go Test / test	1m 11s
Run Main (gnodev) / Go Linter / lint	1m 14s
Run Main (gnodev) / Go Build / generated	7s
Run Main (gnofaucet) / Go Build / generated	12s
Run Main (gnofaucet) / Go Test / test	36s
Run Main (gnokeykc) / Go Linter / lint	34s
Run Main (gnokeykc) / Go Build / generated	12s
Run Main (gnokeykc) / Go Test / test	48s
Run Main (gnomd) / Go Build / generated	7s
Run Main (gnomd) / Go Linter / lint	24s
Run Main (gnomd) / Go Test / test	37s
	6m 40s

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