Remove old oauth code

Author: tschie

src/main/java/com/esri/samples/tiledlayers/export_vector_tiles/AuthenticationDialog.java

@@ -29,9 +29,9 @@
 import com.esri.arcgisruntime.security.UserCredential;
 
 /**
- * Custom dialog for getting an OAuthConfiguration.
+ * Custom dialog for getting a UserCredential.
  */
-class AuthenticationDialog extends Dialog<Credential> {
+class AuthenticationDialog extends Dialog<UserCredential> {
 
   @FXML private TextField username;
   @FXML private PasswordField password;

src/main/java/com/esri/samples/tiledlayers/export_vector_tiles/ExportVectorTilesSample.java

@@ -48,9 +48,7 @@
 import com.esri.arcgisruntime.mapping.view.MapView;
 import com.esri.arcgisruntime.portal.Portal;
 import com.esri.arcgisruntime.portal.PortalItem;
-import com.esri.arcgisruntime.security.AuthenticationManager;
 import com.esri.arcgisruntime.security.Credential;
-import com.esri.arcgisruntime.security.OAuthConfiguration;
 import com.esri.arcgisruntime.symbology.SimpleLineSymbol;
 import com.esri.arcgisruntime.tasks.vectortilecache.ExportVectorTilesJob;
 import com.esri.arcgisruntime.tasks.vectortilecache.ExportVectorTilesParameters;