Shrink signature of channel fallback creation method

app/src/main/kotlin/com/github/gotify/NotificationSupport.kt

@@ -3,6 +3,7 @@ package com.github.gotify
 import android.app.NotificationChannel
 import android.app.NotificationChannelGroup
 import android.app.NotificationManager
+import android.app.Service
 import android.content.Context
 import android.graphics.Color
 import android.os.Build
@@ -99,13 +100,13 @@ internal object NotificationSupport {
     @RequiresApi(api = Build.VERSION_CODES.O)
     fun createChannelIfNonexistent(
         context: Context,
-        notificationManager: NotificationManager,
         groupId: String,
-        groupName: String,
         channelId: String
     ) {
         if (!doesNotificationChannelExist(context, channelId)) {
-            createAppChannels(context, notificationManager, groupId, groupName)
+            val notificationManager = (context as Service)
+                .getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+            createAppChannels(context, notificationManager, groupId, groupId)
         }
     }
 

app/src/main/kotlin/com/github/gotify/service/WebSocketService.kt

@@ -5,7 +5,6 @@ import android.app.Notification
 import android.app.NotificationManager
 import android.app.PendingIntent
 import android.app.Service
-import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
 import android.graphics.Color
@@ -320,8 +319,6 @@ internal class WebSocketService : Service() {
             channelId = NotificationSupport.getChannelID(priority, appId.toString())
             NotificationSupport.createChannelIfNonexistent(
                 this,
-                (this.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager),
-                appId.toString(),
                 appId.toString(),
                 channelId
             )