http service: add pets list length check

0 length lists cause a redis exception from sadd, which I think is not being handled correctly by jedis and leaking the error into further commands

http-service/src/main/java/net/runelite/http/service/chat/ChatController.java

@@ -51,6 +51,7 @@ public class ChatController
 	private static final Pattern STRING_VALIDATION = Pattern.compile("[^a-zA-Z0-9' -]");
 	private static final int STRING_MAX_LENGTH = 50;
 	private static final int MAX_LAYOUT_ROOMS = 16;
+	private static final int MAX_PETS = 256;
 
 	private final Cache<KillCountKey, Integer> killCountCache = CacheBuilder.newBuilder()
 		.expireAfterWrite(2, TimeUnit.MINUTES)
@@ -251,6 +252,11 @@ public class ChatController
 	@PostMapping("/pets")
 	public void submitPetList(@RequestParam String name, @RequestBody int[] petList)
 	{
+		if (petList.length == 0 || petList.length > MAX_PETS)
+		{
+			return;
+		}
+
 		chatService.setPetList(name, petList);
 	}