Fix remaining tslint errors (YAY).

- Also updated ci.yml to ensure that linting failures will break the build.

Fully fixes https://b.corp.google.com/issues/411384603

scripts/check-build-status.js

@@ -1,3 +1,4 @@
+/* eslint-disable no-undef */
 import fs from 'fs';
 import path from 'path';
 import os from 'os'; // Import os module