[TIMOB-14145] iOS: Analytics - If you background an iOS app, the background event does not get sent until next launch

*Details:* If you background an iOS app, the background event does not get sent within the 15 second threshold and does not get sent after the threshold. You will not get that background event until next launch. *On Android now (SDK 3.1.1.X), if you press the back button or home button, the end event does get sent within the 30 second threshold.* *Steps to reproduce:* 0. Make sure you have RightScale opened in a terminal to view analytics 1. Install default app to an iOS device 2. Make sure the device is pointing to the staging wifi 3. Launch the app 4. Then, press the home button to background the app *Actual:* ti.background event is not sent within the 15 seconds threshold and still not sent after the threshold. *Expected:* ti.background event should be sent within the 15 seconds threshold if you background the app.