Setup external/robolectric for SettingsRoboTests

Current failing tests: ab/I64100010182936387
Had to Ignore some of com.android.settings.accessibility tests, which will be fixed separately

Bug: 261728063
Test: atest SettingsRoboTests -- --test-arg com.android.tradefed.testtype.IsolatedHostTest:java-flags:-XX:CompressedClassSpaceSize=3g

Change-Id: I4a0cb992db924936826e0c9808accc78dddb5f30

tests/robotests/src/com/android/settings/accounts/RemoveAccountPreferenceControllerTest.java

@@ -75,7 +75,8 @@ import java.io.IOException;
 @RunWith(RobolectricTestRunner.class)
 @Config(shadows = {
         ShadowUserManager.class,
-        ShadowDevicePolicyManager.class
+        ShadowDevicePolicyManager.class,
+        ShadowFragment.class,
 })
 public class RemoveAccountPreferenceControllerTest {