fix: prevent activity recreation on theme change (#26413)
fix: prevent activity recreation on theme change (#26413)

Summary:
On Android 10 whole activity is recreated when the user changes system theme. We should prevent it by adding `uiMode` in `android:configChanges` key in the default template.

## Changelog

[Android] [Fixed] - Android 10: Prevent activity recreation on theme change
Pull Request resolved: https://github.com/facebook/react-native/pull/26413

Test Plan: NOOP

Differential Revision: D17342811

Pulled By: cpojer

fbshipit-source-id: 2bed9b5f91e1b67451fefe34b02a1129d6c80d15

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