Follow-up: remove onKeyLongPress override from ShowsActivityImpl

The super class implementation in BaseActivity was removed long ago to
improve accessibility with
73eba21 Slide out opened activities.

app/src/main/java/com/battlelancer/seriesguide/shows/ShowsActivityImpl.kt

@@ -5,7 +5,6 @@ package com.battlelancer.seriesguide.shows
 
 import android.content.Intent
 import android.os.Bundle
-import android.view.KeyEvent
 import android.view.View
 import androidx.activity.viewModels
 import androidx.lifecycle.ViewModelProvider
@@ -326,11 +325,6 @@ open class ShowsActivityImpl : BaseTopActivity() {
         ShowsSettings.saveLastShowsTabPosition(this, viewPager.currentItem)
     }
 
-    override fun onKeyLongPress(keyCode: Int, event: KeyEvent): Boolean {
-        // prevent navigating to top activity as this is the top activity
-        return keyCode == KeyEvent.KEYCODE_BACK
-    }
-
     override val snackbarParentView: View
         get() = findViewById(R.id.coordinatorLayoutShows)