Fix LogConsole scroll anchor trasmutation

Fix react mutating the scroll anchor element in LogConsole into a log
line and breaking scroll anchoring to the bottom as a result.

packages/web_ui/src/components/LogConsole.jsx

@@ -100,7 +100,7 @@ export default function LogConsole(props) {
 		<Paragraph code className="instance-console">
 			{pastLines}
 			{lines}
-			<div className="scroll-anchor" ref={anchor} />
+			<div className="scroll-anchor" key="anchor" ref={anchor} />
 		</Paragraph>
 	</>;
 }