Wait for the Platform to start

I followed the installation and usage instructions but still receive CORS issue on app start.

The issue is planned to be fixed. Please refer to [troubleshooting instruction](https://github.com/sneas/ionic-native-http-connection-backend#i-followed-the-installation-and-usage-instructions-but-still-receive-cors-issue-on-app-start) for now.