Remove undefined value on init cli command (#22045)
Remove undefined value on init cli command (#22045)

Summary:
Fixes `undefined` description message when running `react-native init --help` on an existing React Native project.
Pull Request resolved: https://github.com/facebook/react-native/pull/22045

Differential Revision: D12878956

Pulled By: TheSavior

fbshipit-source-id: ede329ca88a02013a6c2f75f1b762d89eacdb34f

janicduplessis/react-native,facebook/react-native,janicduplessis/react-native,arthuralee/react-native,myntra/react-native,arthuralee/react-native,hammerandchisel/react-native,myntra/react-native,pandiaraj44/react-native,exponentjs/react-native,facebook/react-native,javache/react-native,exponentjs/react-native,myntra/react-native,exponentjs/react-native,pandiaraj44/react-native,exponent/react-native,facebook/react-native,facebook/react-native,janicduplessis/react-native,pandiaraj44/react-native,exponent/react-native,facebook/react-native,hoangpham95/react-native,pandiaraj44/react-native,pandiaraj44/react-native,hammerandchisel/react-native,javache/react-native,javache/react-native,exponent/react-native,facebook/react-native,hoangpham95/react-native,exponent/react-native,janicduplessis/react-native,hoangpham95/react-native,hammerandchisel/react-native,arthuralee/react-native,facebook/react-native,pandiaraj44/react-native,javache/react-native,myntra/react-native,facebook/react-native,hoangpham95/react-native,hammerandchisel/react-native,javache/react-native,exponentjs/react-native,exponentjs/react-native,hoangpham95/react-native,exponentjs/react-native,pandiaraj44/react-native,hoangpham95/react-native,pandiaraj44/react-native,exponent/react-native,arthuralee/react-native,exponent/react-native,javache/react-native,javache/react-native,arthuralee/react-native,exponent/react-native,exponentjs/react-native,facebook/react-native,hammerandchisel/react-native,exponentjs/react-native,myntra/react-native,myntra/react-native,hammerandchisel/react-native,hammerandchisel/react-native,janicduplessis/react-native,javache/react-native,janicduplessis/react-native,janicduplessis/react-native,myntra/react-native,hoangpham95/react-native,myntra/react-native,exponent/react-native,hoangpham95/react-native,janicduplessis/react-native,javache/react-native,hammerandchisel/react-native,myntra/react-native