linters: enable scopelint (#3963)

* Pin range scope vars

* Don't disable scopelint

This PR repairs linter errors seen when running the following commands:
golangci-lint run --no-config --disable-all=true --enable=scopelint

Contributes to #3262

libs/common/bit_array_test.go

@@ -232,6 +232,7 @@ func TestJSONMarshalUnmarshal(t *testing.T) {
 	}
 
 	for _, tc := range testCases {
+		tc := tc
 		t.Run(tc.bA.String(), func(t *testing.T) {
 			bz, err := json.Marshal(tc.bA)
 			require.NoError(t, err)