webui: Don't auto-expand last message

Fix for issue #32. This removes the auto-expansion behavior of
the last message in the timeline which was causing messages to
keep expanding and contracting in a jarring way.

Co-Authored-By: sketch <hello@sketch.dev>
diff --git a/webui/src/web-components/sketch-timeline.ts b/webui/src/web-components/sketch-timeline.ts
index 1b31dd2..c612dd8 100644
--- a/webui/src/web-components/sketch-timeline.ts
+++ b/webui/src/web-components/sketch-timeline.ts
@@ -270,7 +270,7 @@
             return html`<sketch-timeline-message
               .message=${message}
               .previousMessage=${previousMessage}
-              .open=${index == this.messages.length - 1}
+              .open=${false}
             ></sketch-timeline-message>`;
           })}
         </div>