[TIMOB-25591] Android: Programmatically check whether app has notification permission on Android.

[ypbnv]

JIRA: https://jira.appcelerator.org/browse/TIMOB-25591

Description:
Expose NotificationManagerCompat.areNotificationsEnabled method.

Note: Different results from this property are returned after a change has been made outside JS runtime, so maybe only check for the default value in a unit test ( I assume it is true by default )?

Test case:
app.js

Ti.API.info('Notifications are enabled - ' + Ti.Android.NotificationManager.areNotificationsEnabled());

[build]

	Messages
📖	💾 Here's the generated SDK zipfile.

Generated by 🚫 dangerJS

[hansemannn]

We need more parity for push notifications. Why not use remoteNotificationsEnabled?

[ypbnv]

That option will also block local notifications, so that wording would not describe it's full effect.

[garymathews]

CR: PASS

@ypbnv But test case needs updating due to lint errors.

[lokeshchdhry]

FR Passed.

areNotificationsEnabled() works as expected.

1. Notifications are enabled by default & areNotificationsEnabled() returns true.
2. After turning off notifications in settings for the app areNotificationsEnabled() returns false.

Studio Ver: 5.0.0.201712081732
SDK Ver: 7.2.0 local build
OS Ver: 10.13.2
Xcode Ver: Xcode 9.2
Appc NPM: 4.2.12
Appc CLI: 7.0.2
Daemon Ver: 1.0.1
Ti CLI Ver: 5.0.14
Alloy Ver: 1.11.0
Node Ver: 8.9.1
NPM Ver: 5.5.1
Java Ver: 1.8.0_101
Devices: ⇨ google Nexus 6P --- Android 8.0.0
⇨ google Nexus 5 --- Android 6.0.1
Emulator: Android 4.1