Clean up before making all setting page render edge-to-edge

These classes are casting view to LinearLayout unnecessarily. Later we
might change the root view away from LinearLayout. The cast will cause
crash.

Bug: 132182711
Test: go through SUW.
Change-Id: Iea31882f8edea0c87ef8e95b4da9b6bffa8ea7d0

src/com/android/settings/SetupEncryptionInterstitial.java

@@ -18,8 +18,6 @@ package com.android.settings;
 
 import android.content.Context;
 import android.content.Intent;
-import android.os.Bundle;
-import android.widget.LinearLayout;
 
 /**
  * Setup Wizard's version of EncryptionInterstitial screen. It inherits the logic and basic
@@ -53,13 +51,6 @@ public class SetupEncryptionInterstitial extends EncryptionInterstitial {
         return SetupEncryptionInterstitialFragment.class.getName().equals(fragmentName);
     }
 
-    @Override
-    protected void onCreate(Bundle savedInstance) {
-        super.onCreate(savedInstance);
-        LinearLayout layout = (LinearLayout) findViewById(R.id.content_parent);
-        layout.setFitsSystemWindows(false);
-    }
-
     public static class SetupEncryptionInterstitialFragment extends EncryptionInterstitialFragment {
     }
 }