*: add nolint comment to deprecated math/rand usages

They are used in tests only.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>

internal/random/random_util.go

@@ -50,5 +50,6 @@ func Uint160() util.Uint160 {
 }
 
 func init() {
+	//nolint:staticcheck
 	rand.Seed(time.Now().UTC().UnixNano())
 }

pkg/network/fuzz_test.go

@@ -11,6 +11,7 @@ import (
 func FuzzMessageDecode(f *testing.F) {
 	for i := 0; i < 100; i++ {
 		seed := make([]byte, rand.Uint32()%1000)
+		//nolint:staticcheck
 		rand.Read(seed)
 		f.Add(seed)
 	}