fix image fallback bug

src/app/chat/components/sidebar.tsx

@@ -18,7 +18,8 @@ export function ChatSidebar({ pubkey }: { pubkey: string }) {
 			<div className="flex flex-col gap-3">
 				<div className="relative h-11 w-11 shrink rounded-md">
 					<Image
-						src={user?.image || DEFAULT_AVATAR}
+						src={user?.image}
+						fallback={DEFAULT_AVATAR}
 						alt={pubkey}
 						className="h-11 w-11 rounded-md object-cover"
 					/>