Remove linting step from dangerfile (#42332)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/42332

Changelog: [Internal]

TSIA - the Danger ESLint plugin we use is outdated and there have been issues with its reliability. We already have [linting jobs on CircleCI](https://github.com/facebook/react-native/blob/6c8dfc89566d27c36f9ca3828bcf3a63dfcb6942/.circleci/configurations/jobs.yml#L5-L74) that overlap with this functionality.

Reviewed By: cortinico

Differential Revision: D52834693

fbshipit-source-id: f2b6cb9c4c560f5c3e66514da1779f14d908ae97