chore: remove unused imports

Author: mlopezFC

src/test/java/com/flowingcode/vaadin/addons/chatassistant/ChatAssistantMarkdownDemo.java

@@ -23,19 +23,13 @@
 import com.flowingcode.vaadin.addons.demo.DemoSource;
 import com.flowingcode.vaadin.addons.demo.SourcePosition;
 import com.google.common.base.Strings;
-import com.vaadin.flow.component.UI;
 import com.vaadin.flow.component.button.Button;
 import com.vaadin.flow.component.dependency.CssImport;
-import com.vaadin.flow.component.html.Span;
-import com.vaadin.flow.component.icon.Icon;
-import com.vaadin.flow.component.icon.VaadinIcon;
-import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
 import com.vaadin.flow.component.orderedlayout.VerticalLayout;
 import com.vaadin.flow.component.textfield.TextArea;
 import com.vaadin.flow.router.PageTitle;
 import com.vaadin.flow.router.Route;
 import java.time.LocalDateTime;
-import java.util.Timer;
 
 @DemoSource(sourcePosition = SourcePosition.PRIMARY)
 @PageTitle("Markdown Demo")