Eslint rule to discourage usage of 'suite.only'

[anthonykim1]

VS Code has something like "local/code-no-test-only": "error", to discourage use of 'suite.only'
Python extension could have something similar something like:

{
  "plugins": ["mocha"],
  "rules": {
    "mocha/no-exclusive-tests": "error"
  }
}

to ensure best practices - prevent slipping suite.only

[anthonykim1]

Would be resolved since we have #24235 (review) now