Remove shared multi select helper from MainActivity

This will cause back stack issues for bottom sheet dialog fragments with multi select. That means, if a bottom sheet dialog fragment is multi selecting, then on back press, it will just dismiss the dialog rather than closing the multi-select toolbar.

This is fixed in the next commit.

app/src/main/java/au/com/shiftyjelly/pocketcasts/ui/MainActivity.kt

@@ -121,7 +121,6 @@ import au.com.shiftyjelly.pocketcasts.views.helper.HasBackstack
 import au.com.shiftyjelly.pocketcasts.views.helper.IntentUtil
 import au.com.shiftyjelly.pocketcasts.views.helper.UiUtil
 import au.com.shiftyjelly.pocketcasts.views.helper.WarningsHelper
-import au.com.shiftyjelly.pocketcasts.views.multiselect.MultiSelectEpisodesHelper
 import com.google.android.material.bottomsheet.BottomSheetBehavior
 import com.google.android.material.snackbar.Snackbar
 import dagger.hilt.android.AndroidEntryPoint
@@ -174,7 +173,6 @@ class MainActivity :
         const val PROMOCODE_REQUEST_CODE = 2
     }
 
-    @Inject lateinit var multiSelectHelper: MultiSelectEpisodesHelper
     @Inject lateinit var playbackManager: PlaybackManager
     @Inject lateinit var podcastManager: PodcastManager
     @Inject lateinit var playlistManager: PlaylistManager
@@ -511,11 +509,6 @@ class MainActivity :
 
     @Suppress("DEPRECATION")
     override fun onBackPressed() {
-        if (multiSelectHelper.isMultiSelecting) {
-            multiSelectHelper.isMultiSelecting = false
-            return
-        }
-
         if (frameBottomSheetBehavior.state != BottomSheetBehavior.STATE_COLLAPSED) {
             frameBottomSheetBehavior.state = BottomSheetBehavior.STATE_COLLAPSED
             return