Crash fix when notification actions is used for foreground service

[arnoldlaishram]

Issue -
When NotificationAction is used for foreground service, getting the below error.

Failed to handle method call
Unhandled Exception: PlatformException(error, Parcelable encountered IOException writing serializable 
object (name = com.dexterous.flutterlocalnotifications.ForegroundServiceStartParameter), null, java.lang.RuntimeException: Parcelable encountered IOException writing serializable 
object (name = com.dexterous.flutterlocalnotifications.ForegroundServiceStartParameter

Upon debugging I found that NotificationAction was not implementing Serializable.

Fix -

Making NotificationAction Serializable to support notification actions when notification is started as foreground service

[MaikuB]

Thanks!