chore: remove unused import

Author: paodb

src/main/java/com/flowingcode/vaadin/addons/rssitems/RssItems.java

@@ -34,7 +34,6 @@
 import com.vaadin.flow.component.HasSize;
 import com.vaadin.flow.component.HasStyle;
 import com.vaadin.flow.component.Tag;
-import com.vaadin.flow.component.UI;
 import com.vaadin.flow.component.dependency.JsModule;
 import com.vaadin.flow.component.dependency.NpmPackage;
 import com.vaadin.flow.component.polymertemplate.PolymerTemplate;