Migrate PaymentSettings to DashboardFragment

- Move preference related logic to controllers.
- Add some test cases for controllers.

Test: manual
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.nfc
      make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.core
      atest SettingsGatewayTest UniquePreferenceTest
Change-Id: I061a194c170f63fab51974f26c24be43d67d6f6f

tests/robotests/src/com/android/settings/nfc/NfcPreferenceControllerTest.java

@@ -17,7 +17,6 @@
 package com.android.settings.nfc;
 
 import static com.google.common.truth.Truth.assertThat;
-
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
 
@@ -26,8 +25,6 @@ import android.nfc.NfcAdapter;
 import android.nfc.NfcManager;
 import android.os.UserManager;
 import android.provider.Settings;
-import androidx.preference.SwitchPreference;
-import androidx.preference.PreferenceScreen;
 
 import com.android.settings.testutils.SettingsRobolectricTestRunner;
 
@@ -42,10 +39,13 @@ import org.robolectric.util.ReflectionHelpers;
 import java.util.ArrayList;
 import java.util.List;
 
+import androidx.preference.PreferenceScreen;
+import androidx.preference.SwitchPreference;
+
 @RunWith(SettingsRobolectricTestRunner.class)
 public class NfcPreferenceControllerTest {
 
-    Context mContext;
+
     @Mock
     private NfcAdapter mNfcAdapter;
     @Mock
@@ -55,6 +55,7 @@ public class NfcPreferenceControllerTest {
     @Mock
     private PreferenceScreen mScreen;
 
+    private Context mContext;
     private SwitchPreference mNfcPreference;
     private NfcPreferenceController mNfcController;