RN upgrade: iOS fixes

details:
- [x] Issue: Warning: “rctbridge required dispatch_sync to load rctdevsettings. this may lead to deadlocks” ; Solution: [refer: https://amanhimself.dev/blog/rctbridge-required-dispatch-sync-to-load-warning/]
- [x] Xcodeproj upgrade in React Native 0.60.0 [refer: react-native-community/upgrade-support#14] —> removed the linked libraries since these dependencies were now being managed by cocoa pods itself
- [x] Use of undeclared identifier FlipperClient [refer: react-native-community/upgrade-support#24 (comment)]
- [x] Issue: “atomic_notify_one<unsigned%20long>” ; Solution: [refer: https://stackoverflow.com/a/70874670/1374730]