--ext flag in the npm run lint command no longer supported

The --ext flag is no longer supported when using a flat config file (eslint.config.js).
Also documented here: https://eslint.org/docs/latest/use/configure/migration-guide#--ext

In package.json `"lint": "eslint . --ext ts,tsx --report-unused-disable-directives --max-warnings 0",`
should be changed to `"lint": "eslint . --report-unused-disable-directives --max-warnings 0",`
