Bump plist and react-native in /example/pushDemo_new

Removes [plist](https://github.com/TooTallNate/node-plist). It's no longer used after updating ancestor dependency [react-native](https://github.com/facebook/react-native). These dependencies need to be updated together.


Removes `plist`

Updates `react-native` from 0.53.3 to 0.70.6
- [Release notes](https://github.com/facebook/react-native/releases)
- [Changelog](https://github.com/facebook/react-native/blob/main/CHANGELOG.md)
- [Commits](facebook/react-native@v0.53.3...v0.70.6)

---
updated-dependencies:
- dependency-name: plist
  dependency-type: indirect
- dependency-name: react-native
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]