fix: RCTRedBox#copyStack
fix: RCTRedBox#copyStack

- use NSPasteboard correctly
- avoid truncating the error message too early
- avoid overwriting the first error with another error (regression from v0.18.3)
- trim whitespace in error message
- fix measurement of error message

ptmt/react-native-macos,ptmt/react-native-macos,ptmt/react-native-macos,ptmt/react-native-macos,ptmt/react-native-macos,ptmt/react-native-macos,ptmt/react-native-macos,ptmt/react-native-macos