fix-missing-self-or-cls is missing self.node_is_selected check #413

All codemods should have logic similar to self.node_is_selected to check if results exist for this codemod. When writing this codemod we forgot to update sonar_issues.json which made the integration test for this codemod pass. However, adding the self.node_is_selected would've alerted us to having forgotten to add a corresponding sonar issue.