SUW: (Not-really-)Spring Cleanup

* Remove unused imports
* Fix a few line length issues
* Convert a few anonymous classes to lambda expressions
* Convert a few global vars to locals
* Remove unused methods
* Add a small local method in MobileDataActivity to shorten repeated calls

Change-Id: Ia10be8b8c98ef3956949f913ddb6bddc185cf1a5

src/org/lineageos/setupwizard/SubBaseActivity.java

@@ -30,7 +30,6 @@ import android.content.ActivityNotFoundException;
 import android.content.Intent;
 import android.os.Bundle;
 import android.util.Log;
-import android.widget.TextView;
 
 public abstract class SubBaseActivity extends BaseSetupWizardActivity {