Remove allowBackup property from manifest

Please remove allowedBackup from AndroidManifest as it conflict when an app setups as false, 

Execution failed for task ':app:processDevDebugManifest'.
> Manifest merger failed : Attribute application@allowBackup value=(false) from AndroidManifest.xml:23:9
  	is also present at com.rockerhieu.emojicon:library:1.0:4:18 value=(true)
  	Suggestion: add 'tools:replace="android:allowBackup"' to <application> element at AndroidManifest.xml:21:5 to override