LSW: Properly set page transition and cleanup definitions on the way

Set slide animation by default and use it in all pages.
Fix wrong/missing slide animations on various transitions like WiFi
and the backup subpage.

Change-Id: I78c87f38eb615379d39c89b43a016ed2ffb98695

src/org/lineageos/setupwizard/SubBaseActivity.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2020 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -148,16 +148,11 @@ public abstract class SubBaseActivity extends BaseSetupWizardActivity {
     }
 
     protected int getSubactivityPreviousTransition() {
-        return TRANSITION_ID_DEFAULT;
+        return TRANSITION_ID_SLIDE;
     }
 
     protected int getSubactivityNextTransition() {
-        return TRANSITION_ID_DEFAULT;
-    }
-
-    @Override
-    protected int getTransition() {
-        return TRANSITION_ID_FADE;
+        return TRANSITION_ID_SLIDE;
     }
 
     @Override