Address some build warnings

app/src/main/java/eu/kanade/tachiyomi/data/backup/BackupRestoreService.kt

@@ -96,7 +96,7 @@ class BackupRestoreService : Service() {
 
     private fun destroyJob() {
         backupRestore?.job?.cancel()
-        ioScope?.cancel()
+        ioScope.cancel()
         if (wakeLock.isHeld) {
             wakeLock.release()
         }

app/src/main/java/eu/kanade/tachiyomi/data/notification/NotificationReceiver.kt

@@ -6,7 +6,7 @@ import android.content.Context
 import android.content.Intent
 import android.net.Uri
 import android.os.Build
-import android.os.Handler
+import androidx.core.content.ContextCompat
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.backup.BackupRestoreService
 import eu.kanade.tachiyomi.data.database.DatabaseHelper
@@ -143,7 +143,7 @@ class NotificationReceiver : BroadcastReceiver() {
      */
     private fun shareFile(context: Context, uri: Uri, fileMimeType: String, notificationId: Int) {
         dismissNotification(context, notificationId)
-        context.startActivity(uri.toShareIntent())
+        context.startActivity(uri.toShareIntent(fileMimeType))
     }
 
     /**
@@ -192,7 +192,7 @@ class NotificationReceiver : BroadcastReceiver() {
      */
     private fun cancelRestore(context: Context, notificationId: Int) {
         BackupRestoreService.stop(context)
-        Handler().post { dismissNotification(context, notificationId) }
+        ContextCompat.getMainExecutor(context).execute { dismissNotification(context, notificationId) }
     }
 
     /**
@@ -203,7 +203,7 @@ class NotificationReceiver : BroadcastReceiver() {
      */
     private fun cancelLibraryUpdate(context: Context, notificationId: Int) {
         LibraryUpdateService.stop(context)
-        Handler().post { dismissNotification(context, notificationId) }
+        ContextCompat.getMainExecutor(context).execute { dismissNotification(context, notificationId) }
     }
 
     /**

app/src/main/java/eu/kanade/tachiyomi/data/track/komga/Komga.kt

@@ -68,7 +68,7 @@ class Komga(private val context: Context, id: Int) : TrackService(id), Unattende
     }
 
     override suspend fun refresh(track: Track): Track {
-        val remoteTrack = api.getTrackSearch(track.tracking_url)!!
+        val remoteTrack = api.getTrackSearch(track.tracking_url)
         track.copyPersonalFrom(remoteTrack)
         track.total_chapters = remoteTrack.total_chapters
         return track