Local notifications do not appear on Android SDK 26

Local notifications do not work properly on Android with SDK version 26. This is important as Google is now requiring Android SDK 26 or later for new apps.

Regression?: No
This occurred in 4.19.2

1. Download the attached project
2. Ensure that the target SDK version in Platform > Android is set to 26
3. Package the project
4. Deploy the packaged project to an Android device
5. Launch the project on the Android device
6. Wait a 30 seconds
   Result: The notification never appears (there may be a vibration, but no notification)
   Expected: The notification appears properly