[iOS] After switching apiKey Amplitude still log events to previous project

We have an environment switcher in our application. On env switch, we restart our app and initialize Amplitude with a new apiKey. But, no matter how many envs we switch, the events still log to the first project

```
AsyncStorage.getItem('API').then(env => {
const ampInstance = Amplitude.getInstance();
if (env && env !== PROD_API) {
ampInstance.init(DEV_ANALYTICS_KEY);
ampInstance.trackingSessionEvents(true);
} else {
ampInstance.init(PROD_ANALYTICS_KEY);
ampInstance.trackingSessionEvents(true);
}
});
```