fix(lint): remove useless (for now) variable

Author: WarningImHack3r

src/routes/package/[...package]/SidePanel.svelte

@@ -59,7 +59,6 @@
 			awaitedOtherReleases = await otherReleases;
 		})();
 	});
-	let isExpanded = $state(false);
 
 	let storedPrereleaseState = persisted(`show-${packageName}-prereleases`, showPrereleases);
 	$effect(() => {