cleanup: resolve nlreturn linter issues

nlreturn linter requires a new line before return
and branch statements except when the return is alone
inside a statement group (such as an if statement) to
increase code clarity. This commit addresses such issues.

Updates: #1586

Signed-off-by: Rakshith R <rar@redhat.com>

internal/rbd/rbd_util_test.go

@@ -131,6 +131,7 @@ func TestValidateImageFeatures(t *testing.T) {
 		err := test.rbdVol.validateImageFeatures(test.imageFeatures)
 		if test.isErr {
 			assert.EqualError(t, err, test.errMsg)
+
 			continue
 		}
 		assert.Nil(t, err)