cleanup: remove unused progressDialog variable

Author: thedroiddiv

AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt

@@ -261,10 +261,6 @@ open class DeckPicker :
     private var shortAnimDuration = 0
     private lateinit var deckPickerContent: RelativeLayout
 
-    // TODO: Encapsulate ProgressDialog within a class to limit the use of deprecated functionality
-    @Suppress("Deprecation")
-    private var progressDialog: android.app.ProgressDialog? = null
-
     private var studyoptionsFrame: View? = null // not lateInit - can be null
 
     @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
@@ -1528,13 +1524,6 @@ open class DeckPicker :
         WidgetStatus.updateInBackground(this@DeckPicker)
     }
 
-    override fun onDestroy() {
-        super.onDestroy()
-        if (progressDialog != null && progressDialog!!.isShowing) {
-            progressDialog!!.dismiss()
-        }
-    }
-
     /**
      * Performs a sync if the conditions are met, e.g. user is logged in, there are changes,
      * and auto sync is enabled.