Don't call sharedApplication in App Extension (#25769)
Don't call sharedApplication in App Extension (#25769)

Summary:
Fixes https://github.com/facebook/react-native/issues/25767 .

## Changelog

[iOS] [Fixed] - Don't call sharedApplication in App Extension
Pull Request resolved: https://github.com/facebook/react-native/pull/25769

Test Plan: RN works in App Extension.

Reviewed By: cpojer

Differential Revision: D16516104

Pulled By: sammy-SC

fbshipit-source-id: 446fd1d88724b783b2afb2369783b9a85b5cc178

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