Add config option to suppress 'Unable to get entity for ID' errors

src/main/java/us/myles/ViaVersion/protocols/protocol1_9to1_8/packets/EntityPackets.java

@@ -183,7 +183,7 @@ public class EntityPackets {
                         EntityTracker tracker = wrapper.user().get(EntityTracker.class);
                         if (tracker.getClientEntityTypes().containsKey(entityID)) {
                             MetadataRewriter.transform(tracker.getClientEntityTypes().get(entityID), metadataList);
-                        } else {
+                        } else if(!((ViaVersionPlugin)ViaVersion.getInstance()).getConfig().getBoolean("suppress-entityid-errors")){
                             System.out.println("Unable to find entity for metadata, entity ID: " + entityID);
                         }
                     }

src/main/resources/config.yml

@@ -21,4 +21,7 @@ bossbar-patch: true
 # If your boss bar flickers on 1.9, set this to 'true'. It will keep all boss bars on 100% (not recommended)
 bossbar-anti-flicker: false
 # This will show the new effect indicator in the top-right corner for 1.9 players.
-use-new-effect-indicator: true
+use-new-effect-indicator: true
+# This will suppress the following error: 'Unable to get entity for ID: xxxx'
+# This error message means one of you plugins is sending bad packets!
+suppress-entityid-errors: false