Don't send ping update twice

VelocityTabListEntry#setLatency calls the update method, which
constructs a new packet and sends it to the client.
The backend packet we are processing also reaches the client, therefore
we are sending the same packet twice.
VelocityTabListEntry#setLatencyInternal is the correct method here.

proxy/src/main/java/com/velocitypowered/proxy/tablist/VelocityTabListLegacy.java

@@ -68,7 +68,7 @@ public class VelocityTabListLegacy extends VelocityTabList {
         if (nameMapping.containsKey(strippedName)) { // ADD_PLAYER also used for updating ping
           VelocityTabListEntry entry = entries.get(nameMapping.get(strippedName));
           if (entry != null) {
-            entry.setLatency(item.getLatency());
+            entry.setLatencyInternal(item.getLatency());
           }
         } else {
           UUID uuid = UUID.randomUUID(); // Use a fake uuid to preserve function of custom entries