android: Remove TwoPaneOnBackPressedCallback

Leftover UI code for dolphin's cheat system. Removing for now.

src/android/app/src/main/java/org/yuzu/yuzu_emu/ui/TwoPaneOnBackPressedCallback.java

@@ -1,37 +0,0 @@
-package org.yuzu.yuzu_emu.ui;
-
-import android.view.View;
-
-import androidx.activity.OnBackPressedCallback;
-import androidx.annotation.NonNull;
-import androidx.slidingpanelayout.widget.SlidingPaneLayout;
-
-public class TwoPaneOnBackPressedCallback extends OnBackPressedCallback
-        implements SlidingPaneLayout.PanelSlideListener {
-    private final SlidingPaneLayout mSlidingPaneLayout;
-
-    public TwoPaneOnBackPressedCallback(@NonNull SlidingPaneLayout slidingPaneLayout) {
-        super(slidingPaneLayout.isSlideable() && slidingPaneLayout.isOpen());
-        mSlidingPaneLayout = slidingPaneLayout;
-        slidingPaneLayout.addPanelSlideListener(this);
-    }
-
-    @Override
-    public void handleOnBackPressed() {
-        mSlidingPaneLayout.close();
-    }
-
-    @Override
-    public void onPanelSlide(@NonNull View panel, float slideOffset) {
-    }
-
-    @Override
-    public void onPanelOpened(@NonNull View panel) {
-        setEnabled(true);
-    }
-
-    @Override
-    public void onPanelClosed(@NonNull View panel) {
-        setEnabled(false);
-    }
-}