Start deep link page synchronously in SettingsActivity

- Use a synchronous API to make SettingsActivity start deep link intent
  in onCreate
- Change SettingsHomepageActivity from an alias to a real activity
- Clean up redundant codes

Fix: 206585572
Test: Manual, robotest build pass
Change-Id: Idf42c026f593bb5801a13cae250d1523030b7092

src/com/android/settings/homepage/SliceDeepLinkHomepageActivity.java

@@ -16,12 +16,6 @@
 
 package com.android.settings.homepage;
 
-import android.content.ComponentName;
-
 /** Activity for Slices to launch Settings deep link page */
 public class SliceDeepLinkHomepageActivity extends SettingsHomepageActivity {
-    @Override
-    protected ComponentName getDeepLinkComponent() {
-        return new ComponentName(getApplicationContext(), getClass());
-    }
 }